December Garden Tips
- Our wet October was followed by a dry November. This means that if you turned off irrigation systems you must water by hand or turn them back on until we get rain again.
- Temperatures dipped in late November to around freezing at night in many parts of the County. It is very important that frost-hardy plants have enough water – especially recent transplants with young root systems – when freezing temperatures hit. More plants die from lack of water in freezing weather than from actually freezing.
- Protect frost-tender plants such as Bougainvillea, Hibiscus, Citrus, Tibuchina, etc. You can use an anti-desiccant such as Cloudcover, and when frost is actually predicted, cover the plants with sheets or lightweight blankets or burlap. A strand of Christmas lights in a tree is often enough to protect the plant from frost, as well (and you get decoration!)
- You can still dig up and divide grasses and perennials – the moist earth, shorter days and cooler weather, combined with the dormancy of the plants, makes this the least stressful time for them to go through this process. Make sure that once you’ve excavated the plant to keep roots moist by keeping the plants in the shade and covering the roots with damp newspaper while you are working.
- You can also continue to plant California Native Plants and most hardy trees and shrubs. Water well after planting. Click here to read the recent "Plant Natives Now" article.
- Stay on top of the deciduous leaves. If you compost, shred the leaves before composting, or run a lawn mower over them. If not shredded they will mat and take forever to decompose, making a slippery, gooey mass in your compost pile or beds. You can put them out for recycling, as well, but why give up all that nice free mulch?
- Feed your lawn with organic fertilizer every six weeks throughout the winter which will keep it healthy but not produce tremendous bursts of growth which will require frequent mowings
- Plant any remaining spring-blooming bulbs.
- Sow and/or transplant vegetables such as lettuce, arugula and peas. Plan your winter vegetable garden (see accompanying article) – in Sonoma County we can harvest something all year ‘round! If you are in colder parts of the County you may need to protect the plants from sustained freezing temperatures, as well, by using floating row covers.
- Harvest cabbage, broccoli, Brussels sprouts, lettuce, root crops and persimmons (now aren’t you sorry that you didn’t plant a fall vegetable garden?)
- Consider getting or building a cold frame. A small cold frame, which can be purchased or built relatively inexpensively, will allow you much more flexibility, especially in vegetable gardening, and give you a big head start on your summer garden, as well.
- Clean, oil and store tools such as shovels, hoes, pruners, etc. Use a light machine oil on metal parts to prevent rust.
- Clean out gutters to avoid overflow and direct water to downspouts.
- Prune pines and other dormant conifers. Don’t trim back individual branches (and whatever you do, don’t top them!). Rather, thin trees where necessary by pruning out entire branches.
- You can "deep prune" lavender, rosemary, rockroses, and other woody perrenials that have gotten too leggy back to just above the lowest folliage--see Rosemary McCreary's Nov 24th article "Pruning Rockroses" on such pruning.
- Winter is the season when rats forage – and damage – our plants. If you have had problems in the past or if your neighbors have noticed rats, put out traps early before the rats devour fruit trees, vines, climbing roses and the like.
- Plant Amaryllis or Paperwhites inside, or get some Pointsettas or bring in evergreen boughs to decorate the house – you will likely be spending more time inside than out in December!
©Sonoma County Master Gardeners