Do you have a gardening question? The UC Master Gardeners of Santa Clara County can help. Its volunteers are part of the University of California’s Cooperative Extension program, and they are trained to use research-based information to educate their fellow residents on sustainable gardening and landscaping practices locally.
Their monthly “Ask a Master Gardener” column in the Palo Alto Weekly will answer your questions and offer tips. This month’s topic is caring for fruit trees and roses amid the winter.
When and how should I prune my fruit trees?
The optimal time to prune most deciduous fruit trees (except apricot and cherry) is right now — January and into the middle of February. This is when most fruit trees are dormant, and since leaves have dropped, you can easily see the structure of the tree and make decisions on where to cut.
Why prune? Pruning is important in controlling the size of your trees so you can easily pick fruit come harvest time. It also lets you regulate the quality and amount of fruit you grow and keeps the tree healthy and strong.
It’s helpful to know where the fruit flowers on your variety of tree. That way, you won’t inadvertently cut off the branches where blossoms will grow.
Once you’re ready to start pruning, remove dead, broken and diseased branches, and any old leaves or fruit. Remove any branches that horizontally cross other branches and may rub against them. Then make cuts to produce desired height and shape and allow sunlight into the center of the tree. That’s important, because branches exposed to sun produce the largest fruit, while shaded branches eventually stop fruiting.
Help bring the sunlight in by trimming the top of the tree and by thinning out some of the interior branches. Remove water sprouts — vigorous vertical growth in the center of the tree — and the suckers that grow from the rootstock at the base of the tree. Always use sharp pruning tools, preferably disinfected with a 10% bleach solution to prevent spreading possible infections.
A note about apricot and cherry trees: Don’t prune apricot and cherry trees in the winter. They are susceptible to Eutypa dieback, a serious fungus that can eventually kill a tree. Instead, apricots and cherries should be pruned in late summer to allow pruning cuts to harden before winter rain and wind spread the Eutypa spores into pruning wounds.
What’s going on with rose care this time of year?
The winter months can be busy ones for rose gardeners. It’s the ideal time for both pruning existing roses as well as adding new ones to the garden.
Pruning: In our area, January is generally the best time to prune roses, even if they are not completely dormant.
The old advice was to cut the canes down drastically, but that isn’t necessary in our climate. Instead, cut back about one-third to one-half of the total height. In other words, take a 4-foot bush down to about 2-3 feet. Always make pruning cuts at an angle about 1/4 inch above a bud that points toward the outside of the plant. The angle should slope away from the bud. A cut made in this location will heal rapidly and water will drain away from the bud.
Improve air flow by taking out any branches that are crossing or growing toward the middle of the plant. Move soil away from the trunk to expose suckers that are connected to the trunk and remove them; just clipping them off where you see them emerge from the soil isn’t effective. Remove spindly canes or those smaller in diameter than the size of a pencil. Clean up old leaves on the plant and ground to reduce rust and black spot.
Selecting new roses: January and February are also great times to plant new roses. Nurseries and online sites are carrying bare-root roses this time of year, giving you the best selection and price. Before heading out to shop, think about where you want to plant the roses. They need six to eight hours of daily sunlight, well-drained soil, and good air circulation. Color of the blossoms and size of the plant are also considerations when choosing which rose varieties to plant.
You may also consider the balance between scent and appearance. Many of the older roses are highly fragrant, while many newer roses are bread for beauty and large blooms.
Once at the nursery, look for plants with plump canes, good green color, white interiors and are disease resistant. Also check their assigned grade. Bare-root roses are graded either grade No. 1, No. 1-1/2 or No. 2, according to their productivity and growth and size once they bloom, with No. 1 being the best plant. While all grades will eventually grow to the same size for the variety of rose, it will take longer for the lower grades as they start with fewer, smaller canes.
