PLANT OF THE MONTH
April, 2009
Plant of the Month Feature
by Joyce Ollie
Arboretum Roots Board Member
Catalpa speciosa
Northern Catalpa
This beautiful deciduous tree can be found just west of the butterfly garden and prairie. There's a bench under the tree waiting for you. One of the larger trees on the arboretum grounds, our Catalpa was grown from a seed by Lou Knockel, a former caretaker at the Arb, and planted in 1975.
The Catalpa is easily recognized by its leaves, flowers, and fruit. The leaves are heart-shaped and huge! They provide dark shade (therefore the bench), and it is said that songbirds like the shelter they provide from wind and rain. The tropical-looking flowers are white with purple markings and are clustered together in 4 to 8 inch panicles. Because the Catalpa blooms in June, it is the last tree to bloom at the arboretum, and the show is worth the wait.
Even more spectacular than the leaves and flowers are the foot-and-a-half long pods that hang from every branch. The pods resemble extra long green beans. They contain many flat seeds with wings that are dispersed by the wind once the pods dry and open. Most of the pods hang on until spring and make a rattling sound when the wind blows.
The Catalpa is native to the rich bottomlands of the central Mississippi River basin. It grows well in a range of soil-types, however, and tolerates a range of moisture levels. It is sometimes called a "Catawba," a Chippewa word. Apparently, a transcription error changed the spelling to Catalpa.
The Catalpa is a host plant for the Catalpa Sphinx moth caterpillar which eats as it ambles across the leaves. This isn't entirely bad news, however, because people who fish, including our own David Horst, like to use the Catalpa "worms" as bait. David also relates that he has Catalpas naturalizing in his pasture.
Years ago, one could buy a Catalpa at any nursery, but they are not commonly sold today. With our meticulously kept lawns, the Catalpa may not be a tree for your yard unless you have an acreage in the country. It would need a large space since it gets 40 to 50 feet tall and 20 to 40 feet wide. And it always seems to be dropping something--pods, petals, leaves, or caterpillar frass!
About the author: Joyce Ollie is a retired special education teacher who enjoys gardening and observing nature. She is a member of the Roots Board and volunteers at the Arboretum by giving tours and planning programs. The Bickelhaupt Arboretum is fortunate to have Joyce on its Roots Board.