Q: We have a lemon tree that’s about 2 years old. It needs to be pruned but it has three healthy stocks. How do we go about pruning it so it’s a tree (with a central trunk) and not a bush? Any advice would be appreciated.
Peggy Holstine, Ione
A: Lemons and other citrus usually grow as multitrunked plants, according to UC master gardener Annie Kempees. One of the first things gardeners tend to do with lemons is attempt to trim them in a way that will make them look like a tree.
When pruning any citrus, begin by removing dead, diseased or broken branches. Remove any “suckers” or shoots growing from below the graft union, which looks like a knot or diagonal scar low down on the main trunk about 6 to 12 inches above the soil line.
Commercial citrus trees are “grafted,” meaning that wood from a tree with desirable fruit is cut and attached to a sturdier disease-resistant root stock. The variety of the root stock adds hardiness to the new grafted tree, but suckers allowed to grow out of the root stock almost always produce inferior fruit and may crowd the grafted main trunk. You don’t want the root stock taking over the tree.
(Another way to tell which stems are which: Growth from the root stock tends to have more thorns.)
Unproductive stems can be removed to allow more light and air to penetrate through the tree canopy; this encourages healthy new growth.
The leaf canopy of a citrus is an important food storage area. Besides removing foliage, pruning removes flowering buds that are often referred to as “fruiting points.” Because citrus blooms and bears fruit on new growth flushes, lopping off branch tips removes flowering buds and reduces yield at harvest.
Take care not to overthin. Direct sunlight on the previously shaded branches and trunk can cause sunburn. Leaving lower branches intact will shade the ground, inhibit weed growth, and produce fruit that is easy to reach.
Experiments have shown that the best results can be expected if pruning takes place in the early spring after the danger of frost has passed and before the start of a new growth cycle.
For more pointers on pruning citrus, check out the cultural notes on the University of California’s integrated pest management website, www.ipm.ucdavis.edu.
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