Extension Educator, Horticulture
Many trees suffer through the murkiness of anonymity most of their days. They maintain their green treeness through the summer unnoticed and unloved except for the casual glances by tree nerds. They tactfully wait to flaunt their beauty when other trees are barren.
Every year I can count on at least one phone call from an observant traveler or basketball fan inquiring as to the identity of the bejeweled trees on the west side of the Assembly Hall. The trees are strikingly resplendent. Every branch of these small wide spreading trees is adorned with dangling clusters of bright red orbs. Most people think of holly for a winter fruit show, but hawthorns are fruitfully magnificent when the backdrop is winter grey.
At first the name hawthorn doesn't sound like anything you would want in a home landscape unless you have visions of impaling marauding squirrels. Several species of hawthorn are available; however hawthorn species vary remarkably in their thorniness, disease resistance and ornamental appeal. Most are wide-spreading small to medium trees of 30 feet tall and similar or wider in their spread. Many species are native to North America.
Several hawthorns fall into the four season appeal category of landscape plants with attractive flowers in spring, glossy leaves, dark red coppery to purple fall color, winter fruit show and attractive bark. Most produce abundant fruits that persist into winter since birds prefer to eat other fruits first. Unfortunately some hawthorns can suffer from numerous diseases and pests such as fireblight and scale. The diseases we see most often on hawthorn are rust diseases. If you are considering a hawthorn, do your homework to make sure the one you have selected shows good disease resistance especially rust resistance. Despite some drawbacks hawthorns are pretty tough trees adapting to a wide range of conditions and are good landscape companions since they cast a light shade.
So what are the trees on the west side of Assembly Hall? Aptly named they are 'Winter King' hawthorns, a cultivar of the native green hawthorn (Crataegus viridis). 'Winter King' has a courteous rounded habit at 25 feet tall with a wider spread. Fruits are vivid red at one half inch in diameter. The abundant fruit persists into winter although the color deepens to a dark red. 'Winter King' is fairly resistant to rust but some years rust may occur on the fruits while the leaves go uninfected. Few thorns are produced on the silver grey stems. As 'Winter King' ages the bark does a dignified strip tease of the grey-brown outer layers to reveal its inner beauty of orange-brown. 'Winter King' deserves its place on many recommended planting lists.
Another hawthorn worth considering is also a native tree, Washington hawthorn (Crataegus phaenopyrum). Slender brown stems give the tree a more delicate appearance in spite of the long thorns. Fruit is glossy red at one fourth inch in diameter. Fruit color appears in late September and continues into winter. Princeton Sentry™ is a vigorous columnar form and its almost thornlessness makes it more usable in home landscapes.
Lavelle hawthorn (Crataegus x lavallei) is a hybrid of four season appeal with eye-catching white spring flowers and lustrous dark green leaves. Autumn brings shades of bronze and copper red to the leaves. Lavelle shows good resistance to rust diseases. It has some thorns but not nearly as numerous as its parentage. Fruit is dark red to orange red at about three-fourths inch in diameter. Fruit colors develop in November and the show continues well into winter.
Hawthorns are not for high traffic pedestrian areas due to the thorns but in the right place, such as around the Assembly Hall, we can safely pass yet still enjoy the winter show. For more info check out http://urbanext.illinois.edu/treeselector/