Plant of the Week: American Holly (Ilex opaca)

The popular holiday song says to "Deck the Halls with Boughs of Holly" during this holiday season and the American Holly is the tree species they are referencing. It has been reported that Christianity has embraced this during the Christmas season because the thorny leaves represent the "crown of thorns" on Jesus' head and the bright red berries represent his blood. It is a magnificent evergreen tree that is pyramidal is shape and typically reaches heights of 15 to 30' tall. The reason this is such a great urban tree is that it tolerates clay soils, air pollution, and deer.  Deer do not like this species because of the thick, leathery, and spiny leaves.  This species is dioecious which means the male and female flowers occur on separate trees.  Hence to get the wonderful red berries, that birds typically love in late winter after numerous frosts have broken down the tannins and other compounds in the fruit, you must have a female tree.  To obtain good fruit set, you should plant one male tree per three female trees and they should not be located any further than 200' apart.  One of the problems of planting this in heavy limestone areas is that the leaves may be chlorotic because the pH is too high.  If this is the case, use a little sulfur to make the soil a bit more acidic. If you wish to keep this as a more shrubby species, you can do that by cutting it back every year to the height you wish to maintain it. There are many, many cultivars of this species in the nursery trade and one of the most prolific fruit producers is 'Jersey Princess.'  The bark is generally smooth and green and is often hidden from view by the dense thicket of leaves in the cultivated varieties.  This is such a popular tree that there is even a society devoted to all things holly and it can be viewed at http://www.hollysocam.org/