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Recent Gardening Questions from the Hotline
ALUM I have been told that I can dip hydrangeas into alum in order to preserve the flowers. Is this true and if so, where could I find alum? Alum powder is found among spices at grocery stores. It is used in pickling recipes as a preservative to maintain crispness and has other uses also like an ingredient in play dough. There are commercial products used to dry flowers which can be found at craft stores or flower marts. If you want to try alum, try it on a couple of stems to make sure that it works in the desired manner. CORN How can I tell when my corn crop is ready to harvest? Check your crop when the ears are plump and the silks have withered. Corn is usually ready to eat about three weeks after the silks first appear. To check, pull back the husks and try popping a kernel with your thumbnail. It should squirt milky juice. Watery juice means that the corn is mature, while a doughy consistency indicates over-maturity. GARDENIA The buds and flowers on my gardenia plant are falling off. Why? Gardenias have certain requirements which if not met make for an unhappy plant. Check out these conditions and see if you are providing what your plant needs to thrive. 1. Summer heat to thrive and bloom well. 2. Does not like adobe soil. Wants fast draining but moisture retentive soil conditioned with plenty of organic matter. 3. Likes to be planted high and well mulched. 4. Except for during the bloom period, likes to be misted in the early morning. 5. Likes high humidity. 6. Does not like low light intensity. LEAF CUTTER BEES Leaf cutter bees are doing some damage to the leaves on some of my roses. How can I get rid of these bees? Leaf cutter bees are beneficial insects and you want them in your garden. The damage they do is minor and does not harm the plant. Even if you did want to get rid of them, it would be very difficult, so, let them BEE. MEXICAN LIME My Mexican lime is not doing very well and does not produce flowers or fruit. Why? Mexican lime is very sensitive to cold and is normally grown in areas which do not experience any frost. You would be better off to try growing a variety more suited to Sonoma County. NECTARINE Some of the fruit on my nectarine tree is split open. What could cause this problem? Many things can cause this problem. Any type of injury, branches rubbing on the fruit for instance, but the most common cause is excessive soil moisture during pit hardening. Over-watering is the likely culprit. Some varieties, for example Heavenly White, split a lot. - as much as 50% of the crop. So it can be a varietal phenomenon too. OAK I have a young oak tree about six feet tall growing in the ground. I would like to transplant it to another area of my garden. What would be the best way to do this transplanting? Oak trees do not transplant well once they are established and have any size to them. Only with very small seedlings are you likely to be successful. You might be successful if you remove a whole lot of soil with root ball with a back hoe into a new site with a hole 3ft deep x 4ft x 4ft--but that's a pretty expensive proposition. It may be easier to just remove the tree and start in the new location with another tree. PEAR When should I harvest my European butter pears? I have tried harvesting at different times, but if I pick them green they don’t ripen, and if I pick them once they start to get soft, they are already going bad inside. European pear varieties are harvested green when they begin to fall off the tree. They are then stored at 33 to 45 degrees for several weeks. As the fruit is then brought up to room temperature, it softens and turns buttery. If allowed to ripen on the tree, certain cells within the fruit called stone cells develop and make the fruit gritty. Since all of the fruit will not be ready at the same time, when the first ones fall from the tree, harvest the large ones and wait until the smaller ones get larger. SQUASH The blossoms on my squash plant are falling off and not producing any squash. What is the problem and what can I do to solve it? Squash, melons and cucumbers belong to the same family and they have a flowering habit unique among vegetable crops. They bear two kinds of flowers, male and female, both on the same plant. In order for fruit set to occur, pollen from the male flower must be transferred to the female flower. The pollen is sticky, so wind-blown pollination does not occur. Honeybees are the principal means by which pollen is transferred from the male to the female flower. Wild honeybees can be rare in some urban neighborhoods, and when bees are absent, fruit set is very poor. If only a few bees are present, partial pollination may occur, resulting in misshapen fruit and low yield. When no bees are present in the garden or the population is too low for good fruit set, you can substitute for the bee by pollinating by hand. This can be a tedious chore. The pollen is yellow and is produced on the structure of the male flower. You can use a small artist’s brush to transfer the pollen, or you can break off a male flower, remove it’s petals to expose the pollen bearing structure, and roll the pollen onto the stigma in the center of the female flower. When hand pollinating, it is important to use only freshly opened flowers. Flowers open early in the morning and are receptive for only one day. The female flower can be recognized by the presence of a miniature fruit at the base of the flower. Male squash flowers are borne on a long, slender stem, while the female flowers are borne on very short stems. TREE WOUNDS A lower branch broke off my plum tree. Should I use that wound sealer compound that I see for sale on this wound?
No. Trees have their own healing ability and do not need a sealer.
APPLE I have a young apple tree which has some fruit on it. The branches are drooping down to the ground. What should I do? Remove most or all of the fruit if this is a young tree. Don’t worry about fruit production for the first couple of years. Concentrate on developing a strong, healthy tree. Prune to develop strong, evenly spaced scaffold branches. Keep narrow-angled crotches from developing. Don’t let side branches outgrow the leader or secondary branches outgrow the primary branches. By concentrating on developing a strong, healthy tree the first few years, you will be assured of a bumper crop for many years in the future. CLAY SOIL We are planning to put in a nice sized garden. Our soil is clay. What can we do besides adding horse manure and compost in order to improve the quality of the soil? Clay soil cannot be changed in one year into ideal, loose soil. However, you are doing the correct thing by adding manure and compost--add lots. Do this annually, and in a few years you will have good soil. Another good alternative is to build up berms--to 2-3 feet of good soil on top of the clay, and plant in those. The drainage in the berms for the new plants will be good, and over time worm, microbial and root activity will begin to increase the quality of the clay underneath. You almost always see advice for clay to add gypsum. But adding calcium sulfate (Gypsum) to clay soil in Sonoma County where we do not have salt (sodium) problems does nothing to help improve soil structure. All it does is add cost. CONTAINER GARDENING It has been suggested to me by a gardening friend that some of my containers in which I have plants could use a soil change. Why would this be necessary? Any sized container has limited space for the plants root system. The contained plant is going to deplete the nutrients of the soil over time. Add compost and/or complete slow release conventional fertilizers and use the soil as a medium to support the plant. If this is done well, the soil should last quite a while. CUCUMBER BEETLES Cucumber beetles are really destroying the blooms on my roses. Is there anything I can do to get rid of these pests? For a pesticide-free approach, and if the infestation is not too intense, cucumber beetles are easy to remove by hand if you do so early in the morning before it warms up. They are slow to move until it warms up a bit. Another approach is to place protective cloth over emerging plants and remove it when plants are old enough to tolerate damage.There are insecticides that are helpful in controlling cucumber beetles on ornamentals. If spraying to control this pest, you only need to spray the tops of the plants where the buds or blooms are, so you do not have to use a lot of toxic material to accomplish your purpose. IRIS When should I cut back the leaves on my iris plants? Unless you are dividing your plants, there is no real reason to cut them back. Just remove any dried or dead leaves. If dividing, trim the leaves and roots to about six inches in length. Let the cut ends heal for several hours to a day before replanting. MAGNOLIA I have a large magnolia tree growing adjacent to a newly planted sod lawn. This lawn has been being watered twice a day for several weeks and now the tree’s leaves are turning brown and the tree appears to be dying. Could there be a connection between all the watering and the decline in the health of the tree? While magnolias make good lawn trees, being watered twice a day for weeks is not in their best interest and certainly could be what is affecting their health. By now the sod lawn should do ok with a regular watering schedule. Let the soil dry out for a while and hopefully the tree will recover. MULBERRY Branches are breaking off my mulberry tree. It has not been pruned back for many years. What should I do? It sounds like your tree could use some pruning. Sometimes branches can get so long that they break from their own weight. Shorten the branches to a well placed, outward growing eye. Hopefully, getting some of the weight off these branches will stop them from breaking. RHUBARB When and how do I harvest and divide my rhubarb plants? Let the plants grow for two full seasons before you start harvesting. In the third season, you can pull off leafstalks for four to five weeks in the spring. Older, huskier plants can take up to eight weeks of harvesting. To harvest leafstalks, grasp them near the base and pull sideways and outward. Do not use a knife to cut stalks because cutting leaves a stub that will decay. Never remove all of the leaves from a single plant. Stop harvesting when slender leafstalks appear. After harvesting, feed and water. Cut out any blossom stalks that appear. Plant the divisions, which contain at least one bud, in late winter or early spring. SOLDIER BEETLES Soldier beetles are all over my elm tree. What should I do about this problem? Nothing. Soldier beetles are beneficial insects--they feed on aphids, caterpillars and grasshopper eggs, and are not harming your tree. TOMATO SEEDLING I have a tomato seedling which I eventually want to grow in a five gallon container. Should I plant it into a one gallon container and let it grow for a while before planting it into the five gallon pot? No. Each time you transplant your tomato, you will just set it back some. Plant it into the largest container you intend to use from the beginning. TULIP I have some tulips which have finished blooming but the plants themselves are not turning brown. I am not watering them. Shall I go ahead and cut them down anyway? You would be better off to be patient. If they are not getting any water, they will turn brown and die down soon enough.
AGAVE I have an agave which has produced a tall, fast growing inflorescence. What can I do to make sure that this plant stays alive? Agaves are succulents with large clumps of fleshy, strap shaped leaves. The flower clusters are big but not colorful. After flowering, which may not occur for years, the foliage clump dies, usually leaving behind suckers that make new plants. The plants shrivel from serious drought but plump up again with watering or rainfall. Provide good drainage. APPLE My mature apple trees are showing some peeling of the bark on the sunny side. I live in a very warm area. What can I do to help my apple trees? Your trees most likely would benefit from a protective coating of white paint on their trunks. Many nurseries sell a prepared paint just for this purpose, or you can use regular latex white paint diluted by half with water. This coating will help prevent further sun damage to the trunks of your trees. ASPARAGUS My asparagus is being attacked by asparagus beetles. How can I get rid of them? Remove spears as soon as possible to avoid damage. Handpick the beetles. Wash eggs, larvae and beetles off with a strong stream of water. Rotenone is also effective. JAPANESE MAPLE The edges on the leaves of my Japanese maple tree are looking burned and dry. What could cause this problem? Japanese maples appreciate shelter from hot, dry, or constant winds. Filtered shade is best, but full sun can be satisfactory if protection is given from the wind. Another possible cause of the leaf problem is salt burn--although not very common in Sonoma County – only in areas near Agua Caliente – Boyes Hot Springs or right next to the ocean. Our wet winters usually leach out any salt buildup. If nothing else has worked try giving your tree an occasional heavy watering to leach out any possible salt buildup in the soil. LEECHES How can I get rid of leeches in my Koi pond without harming the fish? Leeches are best controlled by stocking sunfish or bass in the pond which will eat the leeches. Baiting with fresh pieces of meat tied to a string and then disposing of those captured on the meat has also been effective. Ducks will eat them as well. MIMOSA My three year old mimosa tree is not thriving. It is in a dry area of the garden. Check out the soil moisture in the area where your tree is planted. Mimosas do best with high summer heat and with regular watering will grow fast, but on skimpy moisture it will usually survive but grows slowly and can appear yellowish. OLEANDER Is it safe to put oleander trimmings into my yard waste can which is picked up for recycling? Yes. This material is mixed with a lot of other material which is then composted at a high temperature making it harmless. ONION I planted onion sets around the beginning of April. They are already going to seed and they are only about two inches in diameter. Why? Premature bolting is usually caused by stress, so heat and drought could be the culprit. Try planting your onion sets in the fall to early winter. If you plant them in the spring, use them as green onions. If you want storing onions, do some research before you plant. There are many types of onions and not all of them require the same conditions or are meant to be planted in all areas for optimum performance. RASPBERRIES The lower leaves on some of my raspberry plants turned yellow and then dried up and look burned and brown. What could cause this problem? Assuming that you have eliminated a lack of water as the problem, most likely you have an infestation of spider mites. Mites are encouraged by dusty conditions and hot spells really get them going full bore. Mites are tiny and difficult to detect without the use of a good hand lens. When the infestation becomes bad, usually you will see very small webbing on the leaves. Broad spectrum insecticides do not help and in fact make the problem worse because they kill off any beneficial insects or mites which are present. If the problem is bad enough to warrant action, use a miticide intended for that specific problem. You might also try spraying the leaves and if possible the undersides of the leaves with water several times per day during the heat of the day for a couple of weeks. ROSE The hybrid tea rose bush that I planted a few years ago has so many suckers growing up that I can’t even see the original plant. What can I do about this problem? If the sucker problem is really that bad, you might just want to dig up the plant and replace it with another rose. If there are that many suckers, it might be very difficult to remove them all. In the future, whenever a sucker is noticed growing, dig down to its source and completely remove it by cutting into the area where it comes from. If you just cut it off at ground level, it will re-grow forever. TOMATO I have some tomato plants in small pots in the greenhouse that are very badly wilted. Will fertilizer help bring them back? NO. NEVER fertilize water stressed plants regardless if they are in a pot or in the ground. Water the plants and maybe they will recover, maybe not. If they do recover, plant them out in the garden. My tomato plants look healthy, but the flowers are falling off. What could cause this to happen? Four things can cause this problem. 1. Cool nights. This is most likely your problem since we have had some cold nights this spring. The problem will stop once the temperatures are warmer at nighttime. 2. Hot days. 3. Low light intensity. 4. Smog
APPLE I recently planted a Newton Pippin apple and need to know if it needs another variety of apple for cross pollination. Newton Pippin is self-fruitful but does better with cross pollination. If you decide to plant another apple, Northern Spy, Red Rome and Roxbury Russet share the same late bloom time and would be good choices to plant. AVOCADO I have an avocado tree which is seven years old and about ten feet tall. In the past we have only gotten a few fruits. This year the tree is loaded. I am afraid that there are too many fruits on the tree and we might lose some branches. What are the best guidelines to use when thinning this tree? Usually it is not necessary to thin an avocado, but if you have an unusually heavy crop, to keep from losing branches you might be well-advised to thin the tree. A general rule for thinning a fruit tree is to use your little finger and thumb to space the fruits, then removing any fruit between your fingers. If there still seems to be too many, take more off. If you leave fewer fruits, they will be more able to develop into large avocadoes. CODLING MOTH Is it too late to put pheromone traps out for codling moths? You should start using pheromone traps in mid-March. Make sure to get traps that are specific to codling moth. Place two to four traps in each large tree or one to two traps into smaller trees. Place the traps away from the trunk and preferably near the top of each tree. Unfortunately, it should be noted that home traps do not work very well. The commercial traps are expensive and need to be changed once per month. It may be best just tolerate the damage and cut out the worms and any associated flesh damage at harvest. CRAPE MYRTLE I have a white looking fungus on my crape myrtle tree. What is it and what can I do about it? You have powdery mildew. Apply a fungicide listed for that disease. If you plant anymore crape myrtles, those with “INDIAN” sounding names tend to be resistant to powdery mildew. GRAPES How often do I need to dust my grape vines in order to prevent powdery mildew? As a preventative, thoroughly dust all surfaces of the vines with a fungicide beginning when the shoots are two to four inches long. Repeat at seven to ten day intervals using sulfur. Treating before disease occurs is most important. If disease is already evident, apply wetable sulfur and a wetting agent. Do not apply sulfur if temperatures exceed 90 degrees F. HAWTHORNE I am experiencing some dieback on my Hawthorne tree. The shoots are wilting and look black. What can be the cause of this problem and what should I do about it? Most likely, your tree has fire blight. Eliminate fire blight by pruning diseased branches back at least eight to twelve inches into healthy looking tissue and removing and disposing of all infected tissue. It may be necessary to make cuts even further back into apparently healthy tissue when pruning major branches or making cuts during about May and June when blight bacteria are moving rapidly. LEMON I have an old, well established lemon tree. Something is eating the skins on the lemons during the night. What could be causing this damage? Most likely, snails and or slugs are the problem. Go out after dark or before dawn and look to see if that is the problem. If so, you can use a copper band around the trunk of the tree and also apply some Sluggo or other snail bait around the tree.
ASPARAGUS I have a bed of asparagus that I planted three years ago using started plants. When can I begin to harvest some of the spears? By the third year, you should be able to harvest for about two months, or until the appearance of thin spears indicates that the plants are getting tired of producing more spears. At that point, stop harvesting and let the plants grow. Why do I need to space my rows of asparagus four to six feet apart? Because the roots are going to spread out and multiply into the area that they require. If not spaced with room to grow, your bed will become over-crowded very quickly. I am noticing some brown spots on the tips of my asparagus spears. What could be causing this damage? Most likely, you have asparagus beetles. Look for an insect which is a blue black beetle with red prothorax and yellow spots and red borders on the wings. If they are the problem, prompt removal of the spears reduces the chance of damage. Handpicking of the beetles or washing them off with a strong stream of water can also be helpful. The use of row crop covers would be another option. Rotenone is also an option if you can’t beat them otherwise.
CHEMICAL DISPOSAL I have a container of Roundup which is about two years old. What is the shelf life of such chemicals? If it is no longer good, how can I safely dispose of this or any other chemical product? Most garden chemicals, if stored in a cool place out of direct light should be good for five years. Your two year old Roundup most certainly is still good. You can always call the product’s toll free number and inquire directly. As for disposal of unwanted chemicals, the County landfill on Mecham Road accepts hazardous materials on specific days and times. Contact them for specifics. This service is free to County residents. NEVER dispose of chemicals by dumping them down the toilet or sewer drains. CHICKEN MANURE I have access to fresh chicken manure. Can I speed up the process of cooling it down by liquefying it in water? You can put the manure into burlap bags and soak the bags in water for a month, but this is a stinky, messy process. You would be better off just composting the material until it cools off and breaks down. Fresh chicken manure is a great source of nitrogen for your garden, but adding it fresh will burn the roots on plants, so take the time to compost it correctly, then you will have a great amendment for your garden. CITRUS I have a grapefruit tree which I want to move to another area of the garden. When would be the best time to move this plant? Move your plant in the winter before it blooms and begins to show new growth. COVER CROP This year, for the first time, I grew a cover crop. Is it best to remove the cover crop and put it into the compost pile before using it in the garden, or can I just till it into the soil? Cover crops are meant to be turned directly into the soil. If the crop is tall, it can be helpful to cut it down before tilling it in which just makes it easier to work into the soil without tangling up the tines of your tiller. GINKO TREE Is there anything I can spray onto or do to a Ginko tree to prevent the tree from blooming and fruiting? To prevent a Ginko tree which produces messy, smelly fruit, you should plant a male tree rather than a female tree. If you have already planted a female tree, you could try using a floral fruit eliminator spray, but research indicates spotty results using this method. NARCISSUS I have been growing narcissus in a pot for five years. This year they produced very few flowers. Why? After that length of time, the bulbs are most likely very crowded and small. Let the tops die down completely, then remove the bulbs from the container and store them until fall. Replant with fresh soil in your container and next spring you should experience a much improved bloom. OLIVE My olive tree has been diagnosed with Peacock Spot. How can I prevent this from happening again? Spray with copper fungicides (Bordeaux blend, LiquiCop, etc) immediately after olive harvest (or before the first rain, if fruit is not being harvested) to help to prevent this disease.Olive Peacock spot is a fungus which infects during wet weather and is usually most severe in the lower canopy. Peacock spot will likely never kill an olive tree, but it can cause severe defoliation and a very scraggly looking tree. This is quite often the case in wet winters on varieties that are very susceptible like Mission. Another very similar disease called Cercospora also causes olive tree defoliation. When trees are defoliated, which usually involves most of the 2 year old leaves and sometimes even 1 year old leaves, no fruit is produced. If fruit production is important the trees should be sprayed ideally in the fall before the first major fall rains, but not while fruit is still on the tree. Consequently, the most common timing recommendation is to spray right after harvest. If the winter and spring are very rainy, a second application should be made in late February or March. RABBIT MANURE I have access to fresh rabbit manure. Can I add this manure directly into the garden, or should I compost it first? If you can work it into the garden a month or more prior to planting, fine, if not, you should compost the material before using it. SCALE I have sooty mold on my Oleanders. I have also noticed dark, scaly looking bumps which have been diagnosed as black scale. What are my options in dealing with this problem? The sooty mold is just a bi-product of having the scale infestation. Biological controls and applying certain insecticides are the primary tactics for managing many scale species. Selective pruning of heavily infested plant parts can be helpful in reducing populations. Avoid using broad-spectrum, persistent insecticides because these disrupt natural enemies. Apply narrow-range oil instead, preferably during the dormant season. Narrow-range oils are also effective in spring or summer against scale eggs and crawlers. SOAP ROOT (CHLOROGALUM POMERIDIANUM) What is the best way to get rid of soap root? Soap root grows from a bulb and was actually used by Native Americans for various purposes. To eliminate, mechanical removal is recommended. WALNUT Can I graft English Walnut onto a Black Walnut? Yes. English and Black Walnuts are satisfactory for grafting together. Do this between January and March. BOXELDER BUGS ( SEVERAL QUESTIONS) How can I reduce the population of box elder bugs around my house? They are hanging out on the back wall of the house. Box elder bugs are a pest primarily because high populations in and around buildings annoy people. The bugs cause no actual damage to structures or their contents. If you have any box elder trees, remove them. They support high box elder bug populations. Eliminate debris and litter near homes, especially around foundations in order to reduce the shelter that box elder bugs need to successfully over-winter. Vacuum up bugs that enter the house and screen windows to prevent bugs from entering the home. Pesticides are not recommended. BUDDLEIA (b. davidii) How and when do I prune a buddeleia, b. davidii ? Cut back heavily before spring growth begins. If plant dies down due to freezing weather, it will re-grow from roots like a perennial and bloom the same year. CLEMATIS When is the best time to prune back clematis “ Jackmanii”? Jackmanii produces blooms on new growth. Prune back plant to about one foot high, making sure that there at least two strong sets of buds. Do this in late winter or early spring. MULCH Is it ok to dig composting mulch into the soil in an established rose bed? Use the mulch as a top dressing mulch rather than digging it into the soil. Digging up the soil around your roses will just damage the root system. The mulch will make it’s way down into the soil with the help of worms. LIVE OAK PRUNING When is the best time to prune off lower, overhanging branches on a Coast Live Oak? Old native oaks benefit from periodic grooming to remove dead wood, but thick branches should not be cut unless there is a good reason to do so. To avoid stimulating out-of-season new growth that will be susceptible to mildew and other problems, prune only when they are dormant. With evergreen oaks in the West, this means pruning during the dry season, in mid to late summer. PLANTING PLUM TREES I am planning to put in a home fruit orchard. How close together do I need to plant plum trees in order for them to be able to cross pollinate? Some varieties of plum are self-fruitful, but many are not. Check each variety for it’s requirements concerning cross-pollination. Those that require a different variety need a specific other variety in order to successfully cross-pollinate. The pollenizer trees need to be within bee traveling distance – at least within ½ mile, but closer is better. They do not need to be right next to each other. PRIVET (LIGUSTRUM) I have a privet tree growing in my yard. Now I am getting privet plants coming up wild. Why is this happening and what can I do about it? Privet blossoms are followed by small black berries which birds love to eat, thus distributing seeds. Pull or dig out these shoots when they are small to make the job easier. ROSE OF SHARON (HIBISCUS) How and when do you prune rose of Sharon? Prune during winter. Prune to shape. For bigger flowers, cut back previous seasons growth, cutting down to two buds. SHOTHOLE DISEASE How do I prevent shot hole disease? Apply Bordeaux or a fixed copper fungicide after leaf fall and again before the first fall rains. Additional treatments may be necessary if prolonged wet weather occurs in the spring. Apply Bordeaux or fixed copper fungicides to peaches and nectarines at the pink bud stage. Make applications to almonds and apricots at pink bud and at full bloom. WILLOW (SALIX) I have a few willow trees by a stream near my house and would like to propagate more of them. How do I do this? Take softwood cuttings during late spring or early summer. Plants are making their fastest growth at that time, and the potential for root growth is the best also. Softwood cuttings are especially perishable, so do not allow them to dry out. In making a softwood cutting, cut it from the plant at an angle, rather than straight across. A larger cut surface provides more area for it to callus and root. Make cuttings six to ten inches long. Or, try cutting some branches about ½ inch in diameter and 2 feet long in the winter before any bud activity occurs. Plant them in the ground with only 1-2 buds showing. Water them in or, if rain occurs, don’t bother. Almost 100% will grow. COMPOST I want to add compost to my vegetable garden area. However, I am worried about using the compost available from a supplier like Sonoma Compost which is made and sold at the county dump. Would that material be harmful to the soil due to the use of poisonous plants or plants that might have been exposed to herbicides? Compost manufacturers like Sonoma Compost produce an excellent quality product. The methods used to make the compost are strictly monitored and regulated. Any harmful materials are destroyed by the process used to make the products they sell. Most, but not all potentially harmful things in compost are eliminated in the composting process, BUT any naturally occurring problem like poison oak, eucalyptus, dead skunk all get composted into basic cellulose, humus, amino acids, etc. All the complex compounds that might cause a problem in the “fresh” state are changed into harmless/beneficial compounds. The questionable things might be some pre-emergent herbicides, paint, or something I have not even thought of. The possibility of any of those things getting into the compost in a level that would be toxic is VERY unlikely. CRAPE MYRTLE Do crape myrtles grow well in Sonoma County? What variety is pink? Yes, crape myrtles grow well in Sonoma County. There are several pink varieties available. Check the Sunset Western Garden book for varieties which would interest you. Crape myrtles are susceptible to powdery mildew, but varieties with “Indian” sounding names are resistant. FIG How do you prune a fig tree? Cut back the tops hard at planting. As the tree grows, prune lightly each winter, cutting out dead wood, crossing branches, and low hanging branches that interfere with traffic. Pinch back runaway shoots in any season. Figs can be let go without pruning to give you a huge rambling tree. They can also be cut back severely every year to keep them into any specific shape or size – even espalier. FORSYTHIA (OLEACEAE) I have a beautiful forsythia which I usually prune at the same time that I prune my roses. I am ready to start pruning, but the forsYthia is blooming. Should I prune it now anyway? NO. Forsythia blooms late winter to early spring. It may be blooming a bit early this year, but do not prune it until it is finished blooming. After bloom, prune by cutting to the ground a third of the branches that have flowered. Also, remove the oldest branches and any weak or dead wood. GOPHERS What size wire is best to use as a barrier against gophers and moles? The very best material to use for protection against gophers and moles is one half inch, galvanized hardware cloth. If installed properly, this material is one hundred percent effective and will last many years in the soil. MADRONE (ARBUTUS) My madrone has black spots all over the leaves. What causes this problem and what can I do about it now? Madrone can be susceptible to a fungal disease called TAR SPOT. It is brought on by moist conditions. Make sure your madrone is in a well-drained part of your garden. The plant should survive this disease. Rake up and dispose of fallen leaves. Also, make sure that any water it receives during dry months is non-alkaline water. OLIVE When and how much pruning should be done on an olive tree? Wait to prune olive trees until the winter rains have stopped in order to avoid diseases. Prune during the bloom period. To reduce alternate bearing, remove more shoots from trees with heavy bloom and skip those trees with a light bloom. Also do not prune young trees much or at all until they get about 6-8 ft wide and 7-9 ft. tall. Pruning young trees stunts them. PLASTIC MULCH I want to use black plastic sheeting to mulch my tomatoes. Will the black plastic kill off the beneficial bacteria the soil? No. Black plastic will not harm your soil. ROSES I am putting in a rose garden. Would pea gravel be a good choice for a mulch around the roses? A much better choice for mulching your roses would be compost. If you want the neat look of gravel, use concrete circles, wood, or some other material to create an area around each plant at least 18 to 24 inches in diameter or circumference and use the compost mulch in those areas. Your plants will appreciate the addition of fresh compost each year. I read somewhere that after pruning roses, you should seal all the cuts in order to prevent damage from boring insects. What should be used to accomplish this goal? Commonly used and easy-to-get materials include waterproof Elmer’s glue, clear fingernail polish, shellac or tree sealing compound. Just because you read it does not mean it is true. First, borers that can bore through wood can through glue or fingernail polish or whatever. Second, boring insects are so rare – that treating the wounds is not the bother. Third, boring insects are not any more attracted to the cut surface of a pruning wound than any other stem. TOMATO I have heard that it is a good idea to rotate the spot where you plant tomatoes. What would be a good length to wait before planting in the same location? Planting in a different location, in other words, crop rotation, helps avoid certain diseases which attack tomatoes many other crops. If space is limited, try to wait at least three years before planting tomatoes in the same spot. ARUM How can I get rid of the arum plants growing in my garden? Arum grows from tubers, so the best way to get rid of them would be to dig up the tubers on visible plants or new plants as they emerge. AZALEA The leaves on my azalea are turning yellow. What could be causing this to occur? Azaleas need rich, acid soil that is both moisture retentive and fast draining. If plants turn yellow, wilt or collapse, they are probably suffering from root rot caused by poor drainage. MAPLE When and how should I prune my Maple tree? Medium to large maple species need little pruning. On smaller types, prune to accentuate the natural shape. To minimize sap bleed, make any cuts in summer to early fall in mild climates. Maple trees can actually be pruned any time and sap bleeding is perhaps unsightly, but does not hurt the tree. Probably the best time to do a good job is in the winter when the leaves are off so you can see what you are doing. MEXICAN SAGE My Mexican sage has suffered damage by the recent frosts. Should I cut the plants back now? No. Wait until early spring when you start to see new growth emerging. The old, damaged growth might look bad, but it actually helps to protect the base of the plant from further frost damage. OYSTER SHELL I am using crushed oyster shell in my garden in an effort to deter feral cats from using my garden as their toilet. Will the use of this material have any effect on the ph of my soil? If cats do scratch around and work the oyster shell into your soil, the ph will be raised by 1 unit per 4 ½ lbs. per 100 sq. ft. in sandy loam. Whether this is a good or bad thing would depend on the original ph of the soil and what you desire the ph to be. The acidity or alkalinity of soil is noted as pH (capital H for hydrogen). The acidity is actually the hydrogen ion content of the soil. Adding lots of oyster shell flour will raise the pH, because it is calcium carbonate (lime). I wonder why anyone would think a soil slightly higher in lime content might deter cats from using it as a bathroom? ROSES Can I prune my roses now, and should I spray them after they are pruned? Most local rosarians prefer to prune from mid-January to mid-February. After pruning and removing all leaf debris, spraying with dormant oil can be helpful in killing over-wintering insect eggs, and spraying with a copper based fungicide helps to eliminate fungal spores on the remaining canes and branches. Do any dormant spraying before plants show ½ inch of new growth. SOD WOOD DISPOSAL I have a large quantity of oak from trees which were killed by SOD. What is the proper way to dispose of this wood? Cut the wood up into firewood sized pieces, then immediately enclose the cut up wood from infected trees in heavy, 6 mil, clear plastic sheeting. Leave the wood wrapped up for six months in order to trap and kill any beetles. After that period of time, use it as firewood. Also cover any stumps left in the ground to prevent them from becoming nurseries for beetles. Do not transport infected wood. Chip smaller branches into small pieces and heat treat by enclosing in plastic and leaving in full sun throughout the summer. Then compost or chip and use as a mulch on-site. Wow, that sounds like a lot of work that most people would never do, doesn’t it? Unless the tree is the first one to die in an area, sanitation is likely not worthwhile, since the pathogen is widespread and has been for several years. The primary source of pathogen is live host plants such as California Bay (Umbellularia). The main thing would be to not transport firewood into areas with no history of SOD and spread it into those areas. The best (easiest and most likely) thing to do is just cut it up as firewood and use it in your fireplace or wood stove. Next would be to chip it, but that is very expensive. Beetles are a vector, but insignificant compared to wind-blown rain and splashing water from adjacent California Bay trees. TREE STUMP I had a Mayten tree cut down. Shoots emerge from the remaining stump. Holes were drilled into the stump and I was told to use an herbicide in the holes. Is there anything I can do to get rid of this stump without using toxic materials? The quickest, cleanest, and best method of getting rid of a stump is to have it ground out with a stump grinder. You can rent these machines or have it done by a stump removal service.
AMARYLLIS BELLADONA Where can I find a yellow Naked Lady, or Amaryllis Belladona? Check out local nurseries, or contact the Amaryllis Bulb Company or others on line. Yellow varieties are available. APPLE I know that this is a bit early, but I am going to be away during January and want to know if I will damage my apple trees if I prune them now? The trees are going dormant now, so you should be able to prune them without doing any harm. CURRENTS AND GOOSEBERRIES When and how should I prune my currents and gooseberries? Gooseberries and currents are upright bushes that tend to have crowded branches. Pruning to thin out branches keeps the plant more open. Begin pruning the third year after planting and aim to have nine branches on each plant. Three of the branches should be new, three of them one year old and three of them two years old. Take out the oldest canes and leave three new ones to replace them each year. Do your pruning during winter, the dormant season. MORNING GLORY How can I get rid of morning glory without using chemicals? Getting rid of morning glory without the use of chemicals will be difficult. It is one of the most troublesome and difficult weeds to eliminate because of its extensive root system. The roots may grow 15 to 20 feet deep. Root pieces left behind from hand pulling or spading easily re-sprout. Depending on the size of the problem, you could try repeated mowing, cultivating, digging or even soil solarization. If all this fails, then you might just want to consider a chemical approach. MUSHROOMS How can I kill the mushrooms which are coming up in my lawn? Many people spend a lot of time trying to rid their garden of lawn mushrooms. Removing them as you see them is one method of removal, but it will be a never ending task during several months of the year. Continual removal will keep the appearance of your yard looking good, but the source of the problem will still be present, and lawn mushrooms will most likely return in the future. Chemical removal is another method. As with continual removal, the chemicals will normally kill the mushrooms that are present, but with the food sources for the fungi still present, the mushrooms are likely to return. There is only one way to permanently rid your yard of lawn mushrooms. Exhaust all of the food sources in your yard and soil. Doing a few things can aid in ridding your yard of lawn mushrooms. Clean up all pet waste, dispose of rotting mulch, and have old tree stumps ground out. Having tree stumps ground out may aid in the ridding of lawn mushrooms, but this can cause a type of mushroom called fairy rings to appear. Most lawn mushrooms do not hurt your lawn, but fairy rings can kill grass in certain areas of your lawn. So, as you can see, this is not an easy problem to deal with. PENSTEMON When is the best time to cut back my penstemon? Cut them back in the fall, after they have finished flowering. PERIWINKLE (VINCA) Is periwinkle considered a weed? Periwinkle is commonly cultivated as an ornamental ground cover, but it has escaped cultivation in many places. Under favorable conditions, plants spread invasively and can develop a dense ground cover that out competes other vegetation in natural areas. So, if it is growing where you don’t want it to grow, then it is a weed. PERSIMMONS ( several questions) When is the correct time to harvest my persimmons? There are two types of persimmons, astringent and non-astringent. Both types begin to ripen in late September to November. The astringent types, HACHIYA, can be allowed to become soft-ripe on the tree but are usually harvested when firm-ripe and then allowed to become very soft and ripe at room temperature. The non-astringent type, FUYU, are harvested when they develop their full orange color. To maintain their crispness, protect them from exposure to ethylene produced by other fruit. To harvest the fruit, use hand pruning shears to cut the stem and allow the calyx, the green collar on the fruit, to remain attached to the fruit.
ASHES Can I put the ashes from my fireplace into my compost pile? Because most soils in California have a basic pH and wood ashes are basic, they should not be added to a compost pile. Wood ashes do not decompose. However, most soils in coastal California are acidic. That is they have a low pH, below 7 and could benefit from wood ashes. Also, wood ashes containing several plant nutrients – everything that was in the wood minus the carbon. So, yes there is nothing wrong with applying a bit of wood ashes to the garden, and in fact could be positive. CAMELLIA My camellia plants have black spots on the edges of their leaves and some of these leaves are starting to fall off. What could be causing this problem? Most likely, your plants have bacterial leaf spot. Clean up fallen leaves and apply a fungicide containing copper. CITRUS My citrus tree has a couple of shoots coming from the trunk which are growing straight upwards and are much more vigorous than the rest of the tree. What should I do with these shoots? These are water spouts and should be completely pruned off the tree. CYMBIDIUM When and how should I transplant and repot my Cymbidium? Transplant potted plants when bulbs fill the pot. When dividing, keep at least three healthy bulbs, with foliage, in each division. Dust cuts with sulfur or charcoal to discourage rot. Use a potting medium intended for Cymbidiums. This implies there is a potting medium for every type of plant in the world, which is, of course, not true. Use a well drained potting mix, usually a combination of 1/3 sand, 1/3 peat or compost, and 1/3 perlite, vermiculite, or lava rock. PV DOGWOOD When is the proper time to prune my Chinese dogwood? Do any pruning during the late dormant season to force new growth. GLADIOLUS I dug up my gladiolus bulbs. How do I store them and when should I replant them? Dry the corms on a flat surface in a dark, dry area for two to three weeks. Then store them over the winter in a single layer in flats or ventilated trays in a cool place. Replant them in the spring. NUTGRASS (NUTSEDGE) I am fighting a losing battle with nutgrass. What can you tell me about this weed so that I have a better chance of getting a handle on the problem? Yellow nutsedge is found throughout California, whereas purple nutsedge is found mostly in the southern portions of the state. So, you are most likely dealing with yellow nutsedge. Both types produce tubers, which are incorrectly called “nuts” or “nutlets”, thus the origin of it’s common name. These tubers are produced on rhizomes (underground stems) that grow as deep as 8 to 14 inches below the soil surface. Buds on the tubers sprout and grow to form new plants; thus individual nutsedge plants eventually form patches that can range up to 10 feet or more in diameter. These nudsedges are perennial plants. The majority of tubers can be found in the top 6 inches of soil where they can survive for 1 to 3 years. Tubers are key to perennial nutsedges’ survival. If you can limit production of the tubers, then the nutsedge will eventually be controlled. To limit tuber production, remove small plants before they have five to six leaves. In summer, this is every 2 to 3 weeks. Up to this stage, new tubers have not formed. By removing as much of the plant as possible, the tuber will be forced to produce a new plant, drawing its energy reserves from tuber production to the production of new leaves. However, tubers can re-sprout as many as 10 to 12 times. Even though these newer sprouts start out weaker than the previous ones, they will gradually re-supply the tubers’ energy reserves unless they are removed. The best way to remove small plants is to pull them up by hand or to hand hoe. If you hoe, be sure to dig deeply, at least 8-14 inches to remove the whole plant. Using a tiller to destroy mature plants will only spread the infestation because it moves the tubers around in the soil. Many people mistakenly use systemic herbicides such as glyphosate to try to kill the tubers after the plant is fully grown. Unfortunately, when tubers are mature, there is little translocation of the herbicide from the leaves to the tubers, thus tubers are not affected. If nutsedge is found in small patches in turf, it may be best to dig out the patch at least 8 inches deep, refill, and then seed or sod the patch. Biological control of nutsedge using insects and plant pathogens has been researched, but as of yet has not provided consistent control. In addition to consistently removing small plants, populations can be reduced by shading, drying, mulching with geotextiles, and with properly timed applications of herbicides. The commonly used black polyethylene plastic mulches do not control nutsedge because the sharp points at the ends of their leaves can penetrate them. Landscape fabrics made from polypropylene polymers are available that effectively suppress nutsedge growth. Few herbicides have been effective in controlling nutsedge, either because of lack of selectivity to other plants or lack of uptake. Apply herbicides when they will be most effective. While there are nonselective herbicides currently available to help control nutsedge, they require repeated applications and their use will only result in limited suppression of these weeds. There are also pre-emergent herbicides available to control nutsedge, but they must be applied by a licensed pesticide applicator. No pre-emergent herbicides that control nutsedge can be used on turfgrass.. This is the worst weed we have. If it is a small area in a landscape, I would say tear the whole thing out and start over with good soil that does not contain this weed. That would be expensive, but about the only thing that works. PERSIMMON When should I harvest my Hachiya persimmon? This variety is astringent, meaning that they are not ready to eat until they are soft. However, if left on the tree until they are soft, birds will eat them before you do. Harvest them when they are fully colored but still firm and then let them ripen indoors until they are soft. WALNUTS How do I properly harvest and store my walnuts? Walnuts should be harvested once the green hulls begin to split and the packing tissue between and around the kernel halves has just turned brown. Knock the nuts off the tree rather than letting them fall to the ground in order to prevent insects or other pests from getting to the crop before you do. Remove the nuts from the hulls as soon as possible after harvest. Wash the hulled nuts and spread them out in a shaded, well ventilated location for a few days to complete the curing process. The nuts are fully cured when the kernel of a cracked nut will break cleanly rather than bending. Unshelled walnuts may be stored in a cool, dry, well ventilated location for many months. Once shelled, store frozen for up to a year or refrigerated for three to four months. WEED CONTROL If I use newspaper under a mulch that I am going to apply to control weeds, will the ink give off toxic materials which could harm the soil? NO. Newsprint ink is now soy based ink and will not harm your soil.
ASH Pruning When is the best time to prune my Ash tree?
Prune your Ash tree during the dormant season. BEANS I have been growing the same variety of Italian beans for ten years, saving the seed from year to year. This year, the plants went to seed very early. Why? The beans most likely went to seed because they were not harvested often enough. Don’t leave mature beans on the plants until you are ready to let them mature for seed. Other possibilities for them going to seed are prolonged high temperatures or low or irregular soil moisture which can trigger the plants into shutting down. CUCUMBER My cucumber plants grew ok for a short while, then they developed yellow spots with a gray looking growth. They eventually died. What could be the cause of this problem? Most likely, your cucumber plants became infected with Downy Mildew. This is a fungal disease. There are varieties which are resistant to this disease. Plant resistant varieties next year. DAIKON RADISH How do you grow Daikon radish? Daikon radish are widely grown and eaten by people in China, Korea, the Philippines and Japan. Here is the U.S., they are grown primarily in California and Texas and are sold mostly in Asian specialty markets. They can be sown in spring for summer harvest or in fall for a winter harvest. When buying Daikon seed, make sure that you select a variety that is appropriate for the season. Some varieties such as Miyashige only perform well in the fall, and others, such as Summer Cross No. 3 grow best in the spring and summer. Growing Daikon radishes is very similar to growing any other types of radish. However, Daikon radishes take longer to mature than salad radishes. Sixty days rather than thirty days. They also grow much bigger and so need more space. Sow in rows 18” apart
