There are hundreds of different holly species. But the most popular worldwide are those that we cultivate for their ornamental foliage and black or red berries. Holly bushes look gorgeous in the garden, and holly berries on cut branches make beautifully traditional Christmas decorations.
You can cut branches off your holly bushes during the holiday season, in time for Christmas. But the best time of the year to prune most holly bushes is late in winter or the early weeks of spring. Some are pruned in early summer. Prune your bushes before they start growing again in the new season.
How much can you cut back holly bushes?
Most people prune holly to maintain the natural shape of the holly bushes or to remove unsightly growth. Instead of removing the lower branches, you can let them branch down to the ground.
If holly shrubs get out of hand and need major rejuvenation, you can cut them right down to the ground. Then, the following winter, you can start pruning to create attractively shaped bushes.
If you are trimming evergreen hollies in early summer, the less you prune, the more berries you will get.
What month is best to trim holly bushes?
Timing is important when it comes to trimming and pruning holly shrubs and trees.
While it is best to prune most types of holly in late winter or early spring, you should prune evergreen types in early summer. If you prune in the fall, the new growth won’t have time to harden, and when temperatures plunge in winter, they may be damaged.
In the U.S. and other parts of the northern hemisphere, the most common month to trim holly bushes is March. Spring starts on 20 March. If you are trimming evergreen hollies in early summer, June is the best month, since it is said to start on June 21.
When you spot branches that are dead or diseased, cut them off. It doesn’t matter when it is.
It is, though, best to remove diseased branches when the weather is dry. This is because moisture can increase the risks of infected spores transferring to other parts of your garden.
How to Prune Holly Bushes
According to Encyclopaedia Britannica, there are about 600 species of holly Ilex in the Aquifoliaceae holly family. These range from dwarf holly shrubs as small as 18 inches to large trees that grow to more than 50 feet.
In all instances, it is the female holly that produces the festive red or black holly berries.
Apart from the varieties holly plants offer, there are deciduous hollies and evergreen hollies. There are also hollies that have different growth habits that result in different shapes: rounded hollies, indeterminate hollies, and pyramidal hollies.
As the gardening specialists at the University of Florida’s (UF) Institute of Food and Agricultural Sciences (IFAS) Extension point out, there are different solutions for the proper pruning of trees versus shrubs and hedges. There are also four different reasons for pruning plants:
- To influence fruit or follower production
- To control its growth and/or shape
- To change its appearance
- To encourage plant health
The type of holly you decide to grow will influence the way you prune it.
You need to radically prune deciduous hollies every year. The best time is while they are dormant, late in winter.
Three popular types of hollies Ilex opaca (American holly), Ilex verticillata (Winterberry), and Ilex decidua (Possumhaw) are hardy deciduous hollies. They all lose their leaves in winter, creating an amazing display of red berries, especially when it contrasts against the snow.
Possumhaw and American holly grow in USDA hardiness zones 5-9, Winterberry in zones 5-8, and English holly in zones 7-9.
In the U.S. American holly, which grows into very tall trees, is regarded as the traditional Christmas holly. Winterberry is a small shrub and Possumhaw is a small tree. Winterberry and English hollies are also trees.
You should thin rounded hollies during their first few years of growth. Thereafter, you can concentrate on pruning them so that they retain their rounded natural shape.
Popular rounded species include Japanese holly (Ilex crenata), Inkberry (Ilex glabra), and Yaupon holly (Ilex vomitoria) which grow in zones 5-7, 5-9, and 7-11 respectively. Inkberry and Japanese holly are evergreen shrubs while Yaupon holly is a small deciduous tree that is native to parts of the U.S.
Thin and shape indeterminate hollies throughout their life.
Popular species include Blue holly (Ilex x meserveae), which grows in hardiness zones 5-9, and Chinese holly (Ilex cornuta), which grows in zones 7-9. Both are evergreen hollies.
These hollies are wide at the bottom with tapered tops, forming a pyramidal shape. Although young plants will need thinning, formal shaping isn’t usually necessary.
Popular species include American and English holly (Ilex aquifolium), which is also known as common holly, as well as Nellie R. Stevens holly, which, like English holly, grows in zones 7-9.
While American holly is deciduous, English and Nellie R. Stevens holly (Ilex x Nellie R. Stevens), a cross between English and Chinese holly, is evergreen. It makes a splendid specimen tree.
Ways or techniques to prune holly bushes
In general terms, it’s very important to remove dead damaged wood from holly plants. And, as with all things, the best advice we can offer is to use the right tools for the job.
When you prune holly, always use cutters that have sharp blades that won’t tear the foliage. Loppers and bypass-blade hand pruners are ideal because they won’t crush the plant as anvil types tend to do.
When you prune large branches, use saws intended for pruning trees and shrubs.
Apart from looking unsightly, dead and damaged wood encourages pests and diseases. So, always cut branches back to healthy wood.
Three basic pruning techniques are thinning, shaping, and radical pruning.
Radical pruning is commonly used to cut back vigorous-growing deciduous hollies. Chopping them back radically improves their shape and encourages new growth during the growing season.
It’s never a good idea to remove more than about a third of holly shrubs. But if stems are more than an inch thick, it’s best to cut them to the ground.
If canes are old and spindly, or they stick out from the main body of the plant, remove them.
The idea when thinning holly bushes is to cut branches within the bush to reduce interior bulk and prevent them overcrowding the holly. It helps to increase air circulation within the growing plant and does a good job of preventing disease.
When done properly, thinning won’t be noticeable. If you cut parallel to the main branch the stub that is left behind will be hidden.
After a few years of thinning the interior of the plant, you will find that you need to prune less and less.
The idea when shaping holly bushes is to give them a strong outline. This applies to every possible shape, including straight-forward hedges.
Aim to shorten the branch, rather than remove it. But be sure to make the cut just above a leaf node or bud. Cut at an angle to camouflage the cut end.
It is good practice to ensure that the shape is wider at the base of the shrub. This allows the sun to reach all parts of the plant and prevents the shrub from getting leggy.
Here are some tips on growing hollies.
Where to Plant Hollies
Hollies are happiest in partial shade but usually do okay in full sun. They prefer well-drained soil that is slightly acidic.
How to Plant Hollies
The UF’s IFAS Extension experts advise that you can transplant established holly plants at any time of the year as long as you follow a few basic rules. For instance, make sure the planting hole is one foot wider than the root ball of the plant and a little shallower than its height.
Once you have planted your holly shrubs, water them well. A 2-3 inch layer of organic mulch will help to conserve moisture, control weeds, and maintain the temperature of the soil.
Watering & Fertilizing
Water newly-planted hollies regularly, for three months in USDA plant hardiness zones 9-11 and six months in zone 8, to ensure the plants become well established. The roots need good aeration, so be sure not to let the soil get waterlogged.
Fertilize your newly planted and established hollies in March and September if you want them to grow fast. You can also fertilize if they don’t seem to be doing very well.
Hollies are a reliable, low-maintenance plant, though different holly species do better in certain hardiness zones than others. In general terms, you can certainly find a type of holly that will thrive in zones 5-11.
You can hollies in all kinds of ways within your garden landscape, as foundation plants, specimen or accent plants, or for informal or formal hedges. The bright berries they produce in the wall and in winter will add a splash of color and seasonal touch to any garden.