Begin feeding roses organic fertilizers now
Saturday, March 26, 2005
By Lynne Andresen,
UC Master Gardener Napa Valley rose bushes are putting out lovely new growth now and flower buds are starting to form. In some cases, two or three shoots are coming out of the same bud eye. It's best to remove all but one of these in order to have a strong stem. Select the strongest one or the one that is going in the right direction, usually away from the center of the bush, and carefully rub the others off with your finger.
You might also notice stems that have stopped growing without producing a bud. These are called blind shoots. This usually happens to stems in the middle of the bush that no longer get enough sunlight. Remove them to improve air circulation.
Begin feeding roses now with organic fertilizers. The spring rains will wash their nutrients down into the soil to the roots. One option is pure alfalfa pellets obtained at a feed store. They contain three percent nitrogen, which promotes growth, and a little phosphorus, which stimulates root formation and flowering.
They also contain potassium (potash), which increases disease resistance and makes plants more vigorous. Alfalfa pellets also supply some calcium, sulfur and magnesium, trace elements that are good for your roses. You might want to cover these green alfalfa pellets with a mulch of compost or soil amendment that contains chicken manure, available in our local nurseries. Another option is to use an organic fertilizer that contains alfalfa meal and then cover it with the mulch of your choice.
Organic fertilizers lie dormant until the soil warms and the plant roots can take up the nutrients. Chemical fertilizers act on application, so it's better to use them in the late spring or summer. Liquid fertilizers, whether organic (such as fish emulsion) or chemical (such as MiracleGro), act quickly and the soil and weather must be warmer for the plants to benefit from them.
Because of their quick-acting nature, liquid fertilizers can be used more often, either full strength once a month or weekly at half strength. Water your plants thoroughly the day before fertilizing to prevent leaf burn.
Winter rains usually have weeds popping up everywhere. Remove weeds before mulching or some will work their way through to the surface.
Soon, seemingly out of nowhere, the diseases and insects will come -- on the new buds, under the leaves and on the stems. Control insects with a strong spray of water from the hose. Spray early in the morning so the bushes dry before evening, preventing blackspot, rust and mildew. The hose method also removes the foam that spittlebugs leave. If you choose to use a chemical pesticide, you must reapply it regularly. Follow the instructions on the label and remember to water the day before application to prevent burning the leaves.
With a little care, you'll enjoy a spectacular color display in your garden, with enough blooms to bring into the house and give to friends.
The Napa County Master Gardeners are giving two workshops on growing happy and healthy roses. The first is April 16th from 9:30 to 11:30 a.m. at the University of California Cooperative Extension office at 1710 Soscol Avenue in Napa. The second is April 23 from 9:30 to 11:30 a.m. at Whiting Nursery, 738 Main Street (at Charter Oak), in St. Helena. To reserve a space, call 707-253-4221.