Eric’s Pet Plant: Bald Cypress (Taxodium distichum)

As autumn takes hold over at Marsh Gardens, our friend Eric turns his attention to one of Yale’s more educational plantings, a small native bog display. There’s not much chance his bald cypress trees will attain the majesty of those in the southern swamps, but with any luck they’ll grow large enough to show how much beauty these deciduous conifers can confer on a landscape.

Bald Cypress (Taxodium distichum)

By Eric Larson

Compared to the more colorful denizens of our eastern deciduous forests (and many of the plants here at the garden), Bald Cypress in its subtle autumn raiment is a non-starter. But it provides a fine fall display when viewed in larger stands where it is native, and in winter the leafless trees stand out in all their sculptural splendor.

There are only a few species of deciduous conifers: 13 species of Larch (Larix), the Golden Larch (Pseudolarix), Dawn Redwood (Metasequoia), the Chinese Swamp Cypress (Glyptostrobus) and our plant, Taxodium, of which there are three species – maybe. Some botanists mush them together and make two categories of sub-species for the Mexican species and the Pond Cypress.

Taxodium comes from the resemblance of the leaves to Yew foliage. The Yew genus is Taxus, to which is added the Greek word eidos, which means ‘resemblance, “ and then the whole thing is ‘Latinized.’  It’s a member of the Cypress family, Cupressaceae, along with about a hundred and thirty other species.

Bald Cypress was formerly the dominant species for the great southeastern and southern lowland forests. There were some trees that grew to over a hundred and thirty feet tall. The lumber harvest from a hectare in the early days of ‘forest management’ was over a thousand cubic meters, while today a creditable 150 to 200 c.m. per hectare is common.

The wood is rot resistant, long used for greenhouse construction as well as piers for docks and jetties. Lightweight but strong, with no soft-wood odor, it’s highly prized for its environmental stability.

Bald Cypress trees can grow pretty fast when the basic conditions are met, though it does take a while for the spectacular “knees” to form. They love wet feet, hot humid summers, sunny locations and plenty of nutrients. (Although one species/sub-species is common in less fertile ‘black-water swamps,’ the brown-water swamps of the southeast are generally quite high in nutrient load due to periodic flooding of upland, nutrient-rich waters.)

The shape is generally narrowly pyramidal, although some large crowns have been noted in some plantings, whether by environmental response or genetic disposition. A 70-foot tree will have a spread of around 30 feet, generally speaking.

The northernmost point for native stands of Bald Cypress is Trap Pond in Delaware, a canoeist’s delight. The tree is cold-hardy much farther north, but because young saplings are extremely susceptible to ice damage, a sustainable wild population is not possible in climates where ice often covers the flooded areas necessary for seed germination and initial growth.

On the other hand, trees that are planted as saplings and cared for properly can do well in colder areas all the way to zone 4, and in drier soils (A growth rate of two-and-a-half feet a year for seven years has been recorded in Wichita, KS)

Interestingly, this tree is “exceptionally wind-firm,” as Dirr puts it, and will not be dislodged by even hurricane force winds.

One note: although some coastal tidal inundation has been noted in some of the great stands of Bald Cypress, T. distichum is not suited to growing in brackish water. So avoid this tree in choosing plants for the ‘pond’ plantings along the shores of Rhode Island for instance.

Another note: Bald cypress trees are great for the homeowner with problem wet areas, easy to care for once established, relatively free of pest problems and – of course – unfazed by constant flooding. The species is highly variable, but if you buy a grafted cultivar you can choose from an assortment that includes weepers and columnar forms as well as pyramids. LL

Disclaimer: This column is produced at infrequent intervals, and does not reflect the views of Yale University, Marsh Botanical Garden, or anyone else who works, worked or will work here.