YOUR HALLS WITH BOUGHS OF HOLLY
December 16, 2012
to these questions I have received about holly make a perfect column
for the holiday season.
Are holly trees native to North America? How big do holly trees get?
Where did the idea of using holly at Christmastime originate? Why do
holly leaves have those needlelike spines on them?
The American holly, scientific name Ilex opaca, is native to
the southeastern sector of the United States from New England to the
upper half of Florida to eastern Texas. Hollies also occur naturally
in Pennsylvania, West Virginia and southern Missouri.
everyone knows what a holly tree looks like, but they can reach sizes
that may surprise you. American Forests, an outstanding conservation
organization, has a National Big Tree Program that identifies the largest
individual trees of every species in the United States. Several champion-size
holly trees vie for the record. A tree at the Chelsea Historic Site,
Md., is a co-champion because of a combination of criteria (height,
trunk circumference, and crown spread).
holly, in Alexandria, Va., measures 68 feet from the ground to the top
branch (about as tall as a six-story building). American Forests' website
lists a holly in Chattooga Co., Ga., as the one with the largest circumference
(148 in), whereas the downloadable fall 2012 edition of the "National
Register of Big Trees" cites a tree in Arlington, Va. (154 in).
In either case, two tall men could barely reach around the trunk and
touch their fingers. American holly trees grow slowly, but they can
get really big.
related species, the European holly with the scientific name Ilex
aquifolium became associated with the Christmas season centuries
ago. Like the American holly, the European holly has glossy green, waxy
leaves and bright red berries in winter. A hardy plant whose branches
could be brought indoors to liven up a bleak winter day, holly was probably
first used as decoration by pagan cultures, including the Druids. Christians
also liked the holly's cheerful display and before long it became a
common decoration in many parts of the world, including America. Today,
a variety of cultivated varieties of the two species are commercially
produced in many regions.
ecological perspective, European and American holly trees have a common
trait - a holly tree is either male or female, and the two sexes differ
dramatically. Only the female trees have the bright berries; the male
trees simply have the shiny green, pointed leaves. Bees, wasps, and
other insects pollinate holly trees, and unless a male tree is nearby,
the fruits, that is the berries, of the female tree cannot develop.
So, even though the female tree is the one we consider most impressive
and we prefer for our Christmas wreathes, no berries will appear unless
an unassuming male is in the vicinity.
the ecological explanation for why holly leaves have those needle-sharp
points on the end and sometimes on the sides, the scientific jury is
still out. Some grazing animals might be deterred by having to bite
around a pointed spine, so one idea is that they prevent animals such
as deer from eating them. One proposal, which I checked out on a holly
tree in my backyard, is that the lower leaves have more spines than
the upper ones - the supposition being that grazing deer would be more
likely to eat the lower leaves. Indeed, on my holly tree, most leaves
10 feet above the ground had fewer spines, but we need more data than
my casual examination of a single tree. Another idea is that the spines
are a perfect conduit for freezing rain to run off during an ice storm,
a useful trait for an evergreen tree like holly whose leaves might break
if they were weighted down with ice.
the explanation may be for the pointy leaves, a few branches of holly,
with or without the colorful berries, can add a festive touch to your
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