At the extension office, we receive many questions pertaining to the growth and care of holly shrubs.
Two of the more common questions relate to pruning and berry production.
Question No. 1
Why are some hollies loaded with berries and others are not?
Some years, holly plants are loaded with a bountiful crop of berries. And yet other years, these plants produce few to no berries at all. Here are a few reasons why a holly plant may not produce fruit.
- The plant is a male holly plant. Approximately 50 percent of hollies grown from seed will be male. These plants do not produce berries. Male plants are important, however, as their flowers produce the pollen that is necessary for the fertilization of the flowers on the female (berry-producing) plants. For this reason, it is always advisable to purchase hollies from nurseries instead of collecting them from the woods.
- If holly plants are in deep shade, they may produce very few berries or none at all. Plants growing in heavy shade do not produce enough food to form flower buds.
- Buds are killed by exceptionally cold temperatures during winter. Holly flower buds form in the fall. It is possible for these very small buds to be killed by unseasonable winter temperatures. The open flowers can also be killed by late frosts or freezes.
- Pollination does not occur. The female flowers open but are not pollinated for some reason. Most hollies are pollinated by bees. Cool, wet periods discourage bee activity, and this can greatly reduce the pollination process by bees. Another possibility is that there are no male plants nearby to provide pollen with which to cross pollinate.
Question No. 2
When and how should hollies be pruned?
Where a formal effect is desired, shearing with hedge shears is acceptable. However, it is usually more desirable to retain a natural shape to holly plants. You can groom and reduce plant height by removing large limbs from inside the plant. This allows the removal of undesirable growth without loss of the shrub's natural shape.
Pruning can be done almost anytime of the year on hollies. However, it is undesirable to prune heavily in September and October as this may lead to winter injury to new growth.
Instead, a good time to do heavy pruning is just before growth begins in the spring.
Pruning can be continued during the summer months while the plants are growing.
If you want berries on hollies, do not shear the plants. Shearing removes most of the growth terminals, and this is the growth that produces next year's berries.
When a holly gets too large for its location, it can be cut back to 12-18 inches above ground level and allowed to redevelop.
Although this might appear to be a drastic procedure, new growth will be exceptionally fast as a result. This type of pruning should always be done in the early spring just before new growth begins.
Billy Skaggs is an agricultural agent and Hall County extension coordinator. Phone: 770-531-6988. Fax: 770-531-3994.