Bald cypress (Taxodium distichum): how to identify it

Why a bald cypress goes brown and bare in fall

Most conifers stay green all year, so a bald cypress turning orange in October can look like a dying pine. It is not. Bald cypress is a deciduous conifer: NC State gives its fall color as orange to cinnamon-brown, and the small side branchlets drop soon after with the needles still attached. On the ground under the tree you will find whole feathery sprays rather than single needles, which is a good winter clue.

Only a few conifers do this in North America. The other two you are likely to meet are dawn redwood, a planted tree from China, and the larches, such as tamarack, which carry most of their needles in tufts on short spur shoots instead of in flat sprays. The conifer identification guide covers the evergreen conifers that keep their needles.

In March and April, bald cypress sheds pollen from drooping clusters of tiny male cones 3 to 5 inches long (USDA Forest Service). Those tassels hanging from the twigs are another sign that the tree is alive and a bald cypress.

Bald cypress vs dawn redwood

The two trees are relatives, both deciduous conifers in the cypress family, both planted in wet spots of parks and campuses, and NC State lists each as a tree the other is often confused with. These marks, from NC State's pages on bald cypress and dawn redwood and The Morton Arboretum, tell them apart:

The needle test is the one to trust. The Morton Arboretum gives dawn redwood a mature height of 70 to 100 feet and USDA hardiness zones 4 to 8. For how dawn redwood relates to the two giant redwoods of California, see redwood vs sequoia.

Bald cypress vs pondcypress

Pondcypress grows with bald cypress on the southeastern coastal plain. The Forest Service treats it as a variety of the same species (var. nutans) that grows in shallow ponds and wet areas and reaches west only to southeastern Louisiana. Its typical needles are nearly scale-like and pressed against branchlets that point upward, unlike the flat, spreading sprays of bald cypress. The Forest Service adds three more clues: pondcypress is less likely to have knees and its knees are shorter and more rounded, the ridges on its fluted base are rounded rather than sharp, and its bark is usually more coarsely ridged. It also warns that the two are often hard, and sometimes impossible, to tell apart, because fast-growing pondcypress shoots carry two-ranked needles like bald cypress.

Cypress knees and where bald cypress grows

Knees. The Forest Service says knees are less likely to form when the tree is not flooded, though small knees appear on some unflooded trees, and that "research has found no physiological function for cypress knees"; they may aid aeration but are not critical for survival. NC State repeats the common idea that they help bring oxygen to roots in oxygen-poor mud. Either way, a lawn tree with no knees can still be a bald cypress.

Range. Bald cypress grows wild along the lower Atlantic Coastal Plain from southern Delaware to southern Florida, along the Gulf coastal plain to southeastern Texas, and up the Mississippi Valley to southeastern Oklahoma, southeastern Missouri, southern Illinois and southwestern Indiana. More than 90 percent of natural stands sit on flat ground or in shallow depressions below 100 feet of elevation, often flooded, sometimes 10 feet deep or more. Isolated stands grow at 1,000 to 1,750 feet on the Edwards Plateau of Texas (USDA Forest Service). NC State notes that it tolerates a wide range of soils, so planted trees turn up on dry ground well outside that range.

Size and age. The largest virgin-forest trees were 140 to 150 feet tall and 7 to 12 feet across. Height growth stops at about 200 years. To find a tree again in a different season, for its fall color or its cones, Tree Identifier's Tree Map keeps a pin for every located identification.