Hollies (Ilex spp.), with their sharp spines and bright berries in fall and winter, are a mainstay in the temperate garden landscape. Because they are evergreens, they should never lose large amounts of leaves to browning. If this happens, it could mean that something is wrong. If you address the problem quickly, however, the holly plant should recover.
There are many different kinds of holly. Popular English holly (Ilex aquifolium), hardy in U.S. Department of Agriculture plant hardiness zones 7 through 9, is known for its dark, shiny leaves and bright red berries that people use to festoon homes during the holidays. More prosaic American holly (Ilex opaca) is native to the United States, as its name suggests, and is hardy in USDA zones 5 through 9.
Causes of Brown Leaves
The many reasons a holly’s leaves might turn brown and drop off the tree include overwatering, drought, disease and infestation. If you see browning and leaf drop in large amounts, check to make sure soil is consistently moist but not overwatered, that your hollies don’t have root rot, and that there are no major pests or diseases attacking your tree. Hollies are somewhat tolerant of shade, but like other evergreens may still lose some inner foliage if it's too densely shaded by the outer canopy. This is normal and not a cause for concern.
Chances of Regrowth
Once the foliage on an evergreen tree turns brown, it will never recover. This is not to say that the tree will die or that new foliage won’t regrow, but you should not expect leaves that have turned brown or yellow to turn green again. Instead, the tree will have to grow new leaves from new buds, which could take a while. However, if the loss of leaves was light, you should see healthy new growth in a short time and a fully recovered tree.
Preventing Foliar Damage
If you want to keep the leaves on your hollies from turning brown in the first place, there are a few things you can do. Hollies are adapted to moist, cool conditions and should therefore be kept well hydrated. This prevents them from losing leaves during the heat of summer and drying cold of winter. If one or more of your hollies develops a disease, make sure you prune out the infested branches immediately and dispose of them away from the garden. Clean pruning shears with rubbing alcohol before pruning and between each cut to prevent the spread of disease.
- University of Florida IFAS Extension: Hollies at a Glance
- Clemson Cooperative Extension: Holly Diseases and Insect Pests
- Missouri Botanical Garden: Ilex Opaca
- Missouri Botanical Garden: Ilex Aquifolium
- Kentucky Living Home and Garden: Ask the Gardener -- Archive
- Colorado State University Extension: Leaf Scorch
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