American Holly, select line

Size, growth and what to expect

How fast American holly grows depends on care. One measured tree made just 6 feet of height in 16 years under medium shade, while another reached 22 feet at age 10 after nine years of mowing, mulching and fertilizing. Our growth estimator takes the cautious view and models it as a slow grower, about a foot a year in its youth on an average site. Mature trees on sandy coastal sites stand 15 to 30 feet, and older trees on better ground reach 50 feet, with a crown 18 to 40 feet wide. Trees live 100 years, or 150 at best. The oldest holly in one New Jersey forest was 144 years old. The ages of only a tiny share of trees are ever measured, so older ones may exist.

Seedlings first flower between ages 3 and 9, and only the females carry berries. Seed is abundant nearly every year. The berries run a quarter to half an inch across and hang from September into winter, and at least 18 kinds of birds eat them, including mourning doves and cedar waxwings. The Pilgrims saw in it the English holly of their Christmas customs, hence Christmas holly.

It grows wild from Massachusetts south to central Florida and west to eastern Texas and southeastern Missouri.

How to grow American Holly

American holly grows in full sun, part shade or deep shade. It wants an average, well-drained soil on the acid side and resents standing water. In the colder half of its range, shelter it from winter wind and sun, which brown the leaves. Mature trees carry a pyramidal crown, so set it 15 feet from walls and other trees. Set trees 15 feet apart for a screen.

Saplings ship potted. Because it is a broadleaf evergreen, holly establishes best planted in spring or early fall with its root ball intact. Dig a hole two or three times wider than the root ball and no deeper, tease out any circling roots, and set the root flare at grade. Backfill with the native soil and mulch a wide ring, kept off the trunk. Seed has a deep dormancy. Clean it from the berries and sow it outdoors in fall, a quarter inch deep under mulch. Seedlings come up in the second or even the third spring.

Water every week through the first summer and into fall. Deer browse young hollies in hard winters, so cage the plant until it is above head height. Holly needs no pruning.

Holly is dioecious. Only females bear berries, and they need a male nearby, so plant several seedlings or add a known male. Old leaves drop each spring; that is normal. Eating the berries can make a person mildly ill.