Thorn Trees

Of the several hundred species of hawthorns native over the entire United States, one stands out prominently as an excellent ornamental tree. It is Crataegus phaenopyrum, the Washington Thorn which does well all across the country.

Seldom is this tree found growing more than 30 feet high. In fact, the largest tree on record, according to the American Forestry Association, is at Laurel, Maryland. It measures 2 feet, 9 inches, in trunk circumference and 25 feet in height and has a 23-foot branch span.

The single white flowers, about 1/2 inch in diameter but borne in many-flowered clusters, appear in mid-June. One of the last hawthorns to bloom, the Washington hawthorne flowers at a time when few other ornamental trees bloom.

Just as important as its flowers are the clusters of bright red fruits. The berries are about 1/4 inch in diameter, and begin to color brightly in early fall.

One of the first things one notices about this tree is its habit. Not definitely fastigiate (erect and columnar), it is nevertheless upright in habit of growth. And with a very small amount of trimming, it can quickly be made to appear fastigiate.

This is a big asset, for the tree is frequently used in highway planting… often in the narrow strip between divided highways, where it helps cut down the headline glare at night.

Like all hawthorns, it seems to withstand poor soil and drought, two reasons why it is so successful in city gardens. It is not superior to the tree-of-heaven or the sumacs in this respect, but it will withstand difficult growing conditions.

The autumn color of the foliage is an excellent glossy red to orange, another reason for considering this tree of year-round interest. The dense twiggy habit and the numerous inch-long thorns make it an excellent barrier plant, and it withstands clipping into hedge form very well indeed. Its general habit and ornamental qualities make it useful as a specimen tree also.

However, this excellent tree is not immune to the troubles common to most hawthorns.

Lacebug and red spider may attack the foliage in summer. Sprays for both these pests are not difficult to time properly.

Fire blight can trouble many thorns as well as apples, pears and cotoneaster’s. Controlling this disease is difficult but all dead or dying branches should be removed as soon as noticed and burned.

Borers, too, cause trouble occasionally, getting into the trunks and limbs.

And all hawthorns are alternate hosts for the cedar apple rust. Therefore, if the red cedar is prevalent within a radius of one mile from a proposed planting site, this Washington Thorn should be considered carefully before it is planted to any great extent.