Rose pruning for the Central Valley should be completed now. In the pictures below you can see how much growth rose bushes get throughout the year. The "B" pictures, before pruning, were taken in October. The "A" pictures were taken in early March after they had been pruned.
After you have spent so much time pruning it would be nice just to sit back and wait for the first "show of the year." But there are still things that need to be done. If you didn't get a chance to dormant spray with a copper oil spray or a lime-sulfur spray you can still apply an all-purpose year around dormant spray. This will help control fungus diseases that may have wintered over in dead leaves around your bushes. A year-around pesticidal oil can also be applied for control of several kinds of insects.
Walking Your Garden.
After you have finished pruning, "walk your garden" and look at the plants to make sure you didn't miss pruning any bushes or left some canes too tall. Also check to see if there is any die back on the canes. If there is cut the dead portion of the cane back to where new growth can be seen. See if your
pruning has produced one of the objectives of pruning-to produce new basal canes. I have spent about six weeks pruning, so some of the first bushes that were pruned should be showing new growth. Pictured below is the hybrid tea, Selfridges. The top picture shows the bush when it was pruned in early January. The bottom picture shows the bush about two months after if was pruned. And there are three new basal canes!! One is between the two upper canes. The other two are close to the bottom of the picture between the bottom two canes.
Ideally it would be great if every rose bush would produce new basal canes every year. Good pruning techiques will help stimulate new basal canes, but good fertilizing techiques
can also help stimulate new growth and is necessary for good bloom and growth throughout the blooming season.
Now is the time to start your fertilizing program for the year. There are several types of fertilizer to use. Granular, foliar, systemic, time release and some with weed and insect control. Your needs and preferences will determine which fertilizer to use. All types will have a benefit. You may want to use two different types and alternate your feeding schedule. This will give your roses a more balance of nutrients. The SJVRS has developed a spring start-up fertilizer that combines several ingredients that produce a balance of nutrients as well as many trace elements that rose bushes need. It is applied once in the early spring. The ingredients may be hard to find but with over twenty years of growing roses I go out of my way to find the ingredients. Alfalfa meals with molasses is not recommended. Alfalfa meals pellets or cubes can be broken up before adding to the other ingredients. Cottonseed meal can be found at some nurseries and animal feed stores. The other ingredients should be easy to find. The "reciepe" is : 50 lbs. alfalfa meal, 25 lbs. cottonseed meal, 20 lbs. ironite, 15 lbs. all purpose rose food(not a systemic), 10 lbs. epsom salt, 10 lbs. bone meal and 10 lbs. blood meal. Mix all ingredients. Use 4 cups mix for hybrid teas, grandifloras, and floribundas; 6 cups mix for climbing roses and 1 1/2 cups for miniature roses. The proportions of the ingredients can vary depending on your soil and water conditions.(I use less epsom salt because my water has a high salt content.) After the start-up fertilizer is applied a commercial fertilizer will be applied in one month and continued until mid-September.
The numbers on the fertilizer label are the available nutrients in the fertilizer. 8-12-4 are common nutrient numbers for rose fertilizer. The number 8 is the total amount of nitrogen. 12 is the availabe phosphate and 4 is the soluable potash available. Nitrogen is needed for plant cell growth and plant respiration. Phosphate is necessary for root and stem growth and color and substance in the blooms. Potassium is necessary for the formation of sugars and starches, roots and stems and also for the color and substance in the blooms. 20-20-20, 23-19-17, 5-10-10, 15-30-15 and 18-24-16 are other rose fertilizers with a different combination of the main three nutrients needed for good growth and flower production throughtout the year. Fish meal or fish emulsion is beneficial to roses. It should be applied at a different time than your regular rose fertilizer to prevent over fertilization..
Other trace minerals and minor elements needed by roses are: calcium, magnesium, sulfur, iron, boron, manganese, zinc, copper and molybdenum. They are needed for cell growth and root development, green pigment for chlorophyll, regulation in the respiration in the plant cells, transfering sugar from cell to cell, proper leaf formation and production of the enzyme system.
As the new foliage leafs out spring fungus and insect problems can occur. Powdery mildew is the most common fungus problem to develop in the spring. Cool nights, warm days and high humidity are the ideal conditions for powdery mildew. Below in the picture are powdery mildew spores on new spring growth. Powdery mildew can be deteced before the white spores can be seen on the leaves. Inward curling of new leaves will develop before you see the mildew spores. Powdery mildew will not go away by itself. A mixture of 1 tablespoon of lightweight horticultural oil available from a nursery and 1 tablespoon baking soda in 1 gallon of water can be applied to the damaged leaves. If there is a severe outbreak of powdery mildew a spray that contains triforine should be applied. Triiforine will also control blackspot and rust on roses. If you do not want to apply any type of spray you can cut off the infected leaves of the plant.
Downy mildew is a systemic fungus disease that can occur in later spring when the days are warmer and the humidity is high-at least 85%. The evenings need to have a temperature range of 55 degrees F to 65 degrees F. Downy mildew has no resemblance to powdery mildew so the symptoms may be misconceived. Symptoms include dark irregular splotches on the leaves, some leaves with yellow sections and defoliation of good leaves. Sometimes it can be confused with blackspot. If you have conditions similar take some damaged leaves to your nurseryman for confirmation. If you can confirm you have downy mildew cut back the defoliated plant. Clean up all infected leaves and spray with Daconil 2787. Apply it only in the morning before hot mid-day heat. Another product that controls downy mildew is Monterey Aliette-R. Again, check with your local nursery as to what they feel is the best control for your situation.
Aphids can be a real pest on tender, new spring leaves and buds. You can spray with an insecticidal soap or several different insecticides can be used. 1 tablespoon of a mild soap in 1 gallon of water may contol a light infestation of aphids.
With the beginning of spring comes a lot of careful planning of feeding your roses and watching for insects and diseases that can get out of hand if not controlled. By taking a little time in your garden in early spring you will have a rewarding amount of beauty when you see your first "show of the year" starting in mid-April.
If you have any questions or comments, my e-mail address:
Last updated January 24, 2002
@1997 Linda Burg