It's time for the last installment of our Top 15 Trees in the Parks series. The final four trees include some natives you may not be familiar with, as well as the brightest star in the winter landscape.
12. Eastern hophornbeam (Ostrya virginiana)
This is a small tree in the birch family with an extremely durable wood (which explains another of its common names, “ironwood”). It grows well in many types of soils and can tolerate living under the shade of taller trees. When it matures, its bark appears shredded because it forms narrow strips that are loose at the edges. Leaves are simple, shaped similarly to elms, and doubly toothed at the edges. The fruit, which resembles hops, is a cluster of papery oval sacs each containing a tiny nut.
Like the northern pin oak, this tree has both male and female flowers. Its male flowers are brown “pre-formed” catkins, in clusters of three like birds’ toes, that are visible throughout the winter and open in spring. Female catkins are light green and only appear in the spring. This is a good way to distinguish this species from the American hornbeam (Carpinus caroliniana), whose catkins all appear in the spring.
Phil Says: These trees are often confused with elms because they look very similar with bark characteristics, form, and the nature of the twigs. But upon close inspection, you’ll see subtle differences in leaf shape and seed set. Hophornbeam is a great native that is definitely underutilized in both landscape and urban woodlands. It performs very well as a street tree if planted.
13. Hackberry (Celtis occidentalis)
The hackberry tree is a member of the elm family. It has a distinctive bark—it’s mostly smooth, light brown or gray, but wart-like knobs disrupt the surface. It’s well-suited to the urban environment, tolerant of air pollution and many different temperatures and soil types. It can also be planted near waterways to help reduce the risk of flooding.
The hackberry is a fantastic tree for wildlife, hosting bees, birds, and butterflies. The birds love its sweet fruit, and butterflies (like the hackberry emperor) drink its sap. Humans can eat the berries too, and although they’re fairly thin and dry, they have a taste similar to dates. Another good quality for wildlife is that the hackberry has fairly weak wood, so late in its lifespan it begins to split and form cavities that provide shelter.
Phil Says: Another great native. Definitely underutilized in our landscape and streetscape. They are beneficial in both those settings, and it’s a great woodland tree as well. It has an interesting bark that grows in bumpy ridges. I liken it to the Velcro tree—if you were to run and jump and grab onto it, it would be difficult to slide down the tree because the ridges are so rough they’d hold you there.
14. Yellow buckeye (Aesculus flava)
The yellow buckeye is a close relative of the Ohio buckeye (Aesculus glabra), but can be distinguished by its flowers. In the yellow buckeye, the stamens are shorter than the petals, and in Ohio buckeye they are longer. Both trees have an unpleasant odor, but the Ohio buckeye’s is much stronger, which has led to the yellow buckeye sometimes being termed “sweet buckeye.” The yellow buckeye is also a larger tree.
Its leaf is distinctive, usually having five leaflets. It’s similar to the horse chestnut, which is in the same family of trees. (The leaf buds of the horse chestnut are very sticky, which is a helpful way to distinguish them.) The yellow buckeye’s flowers are yellow and form upright clusters. The fruit, a smooth nut enclosed in a thick husk, is poisonous to humans but beloved by squirrels.
Phil Says: There are native and non-native buckeyes here; there are probably a half-dozen non-natives that have been hybridized in horticulture and brought to this area. They do grow in the parks as well. I don’t plant them in the landscape because there’s a pretty common leaf blight that affects them, so often they get pretty brown by July. But they’re part of the ecosystem, so they’re appropriate for growing in the woods.
15. Witch hazel (Hamamelis virginiana)
Unlike most other trees, the witch hazel is easiest to identify in the winter months. It begins showing its small, thread-like yellow flowers in late fall and retains them throughout the winter. In very cold weather the petals might curl up close, but they usually last until spring, when everything else begins to bloom. Then the small buttons that contain the seed pods burst and shoot out the seeds that have been ripening over the past year.
The witch hazel is a small, shrubby tree, well-suited to the understory. Its scientific name Hamamelis means “together with fruit,” which refers to the fact that its fruit, flowers, and leaf buds all appear at the same time (making it unique among trees native to North America).
Phil Says: That is a great native plant that blooms during the winter when nothing else blooms. It does best in wet, riparian areas, but it is adaptable. It’s a smaller tree, usually multi-stemmed.
We hope you enjoyed this peek into the composition of our forests. Any other trees you'd like to see spotlighted here on the blog?