Posted by Brent Wilson on 8/29/2016 to Pruning Tips
Holly of any type require no pruning at all. That said, they respond well to it. The choice to prune is up to you. Pruning methods for hollies will differ based upon the type of holly and whether or not they produce berries, and the desired form and function in the landscape. Some dwarf holly, such as 'Carissa' and Dwarf Burfordi, will maintain a dense rounded or mounded form with no pruning at all.
When to Prune A Holly
Holly that produce berries should be pruned in late winter, before new growth begins to emerge in spring and after threat of severe cold temperatures has passed. Tiny flowers will be produced early in spring that will then set green berries which eventually turn to red or other colors in fall. Any heavy pruning after flowering will reduce or eliminate berry production.
Non berry producing hollies can be pruned almost any time of year. That said, to avoid damaging new growth stimulated by pruning, cease pruning two months prior to the first frost date in your area. Pruning may resume after plants have gone dormant in winter.
How To Prune A Holly
How you prune a holly shrub or tree will depend on the desired shape and form. Dwarf hollies are typically grown as shrubs while taller growing hollies can be grown as a large shrub or lower branches can be removed to form an attractive small tree.
Selective Pruning Of Large-Leaved Hollies
When it comes to pruning large-leaved hollies, such as Chinese holly varieties, I always suggest selective pruning, which is primarily the removal of foliage and stems so that the plant maintains its natural shape.
The first step in pruning a holly is to remove damaged, diseased, or dead branches. These branches should be cut using sharp bypass hand pruners or loppers at a point several inches beyond the damage or at their origin. When removing an entire branch, be careful not to cut so closely as to gouge the wood on intersecting trunk or branch.
Note: When pruning a diseased plant, it's safest to disinfect pruning tools between each cut when pruning diseased branches.
After removing damaged or dead plant parts, you can prune stray stems that are spoiling the natural shape of the plant. To prune a stray stem, make an angled cut just above a leaf node that will produce new shoots.
Shearing Of Small-Leaved Hollies
Small-leaved holly, such as the Japanese (Ilex crenata) and Yaupon hollies (Ilex vomitoria), respond very well to shearing with hedge clippers or trimmers, which is the reason they're often used in landscape design as tightly-clipped hedges and various formal shapes.
Know that every time you indiscriminately shear an entire plant it will then expend energy to produce new growth. Too many shearings in a season can compromise the health of a plant by causing it to expend too much vital energy. Therefore, I recommend no more than two to three shearings per year; one in early or late winter, when the plant is dormant, and again in late spring and maybe mid-summer.
When forming a hedge or shape, it's a good idea to keep the top branches shorter than the lower branches so all branches receive good sunlight. In other words, the top of the hedge or plant should be at least slightly more narrow that at the bottom of the plant.
Note: Cease shearing plants two months prior to the average first-frost date in your area.
Tree-Forming A Tall Holly
Tree form plants will command much more attention than the same plant in shrub form. If space is limited, sometimes a tree will fit where a shrub won't. Too, if a large holly as outgrown the space it was intended to fill, and is growing out and over a walkway, tree forming can be an option that allows people to walk under the tree.
Many types of holly, such as Nelli R. Stevens, Fosteri, Needlepoint, Burfordi, and Yaupon, are excellent candidates for tree-forming. As trees, these holly are ideal for use as attractive, eye-catching specimens in the landscape.
The goal in tree forming is to have a plant with a dense canopy atop one or more bare trunks. If you want to train holly shrub into a small tree with a single or multiple trunks, start with a plant that is several years old or three or more feet in height.
Since tree forming often requires the removal of a good number of branches, I highly suggest performing this type of pruning during winter, when the plant is dormant.
Before removing any branches, study your holly to decide how many or which trunk(s) you'll want to keep. Then visualize or sketch on paper the desired form and shape.
If you're lucky, there will be only 1 to 3 trunks, and you can keep 1 or all of these. That said, it's okay to have more than 3 trunks. If you intend to remove a trunk(s) cut them off 1/4" above the ground, or from the base of the trunk. Before removing a trunk follow it's branches upward to see where they go, making sure that removing will not spoil the shape of the canopy.
After you've selected and removed any unwanted trunks, you can start removing lower branches. Remove the lowest lateral (horizontal) branch growing from the trunk, making your cut as close to the trunk as possible without gouging into the trunk. After the removal of a branch, step back to take a look at the effect. Then select and remove another branch and so on moving upwards to a desired height that is satisfying in appearance. I usually remove no more than half of the branches on a shrub during a single pruning.
Note: The use of pruning sealer is not necessary though you may use it if you want.
This is a drastic form of pruning used in an attempt to rejuvenate an old holly or to reduce the size of an overgrown holly that has outgrown the space it was intended to fill. Plants that require rejuvenation can be hard pruned in late winter to almost any height, even to a height of 6 to 12 inches above the ground. If the plant survives the pruning you should see new growth begin to emerge in spring.
Note: Plants that are severely stressed or in poor health may not survive this severe level of pruning. But, if your plant is in very bad health, or will require removal if allowed to continue to grow, what have you got to lose?
Plant Long & Prosper!™
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