Most people think of bald cypress (Taxodiumdistichum - Zones 5-11) growing in the hot, humid alligator swamps of the coastal Southeastern United States, often festooned with Spanish moss, but its current natural range extends along the coast from Delaware to Texas and up the Mississippi River valley into Illinois.
One hundred million years ago, when the land was warmer and wetter, the bald cypress's range extended north to present day Canada. Many botanists believe that Washington, DC, like much of the eastern coast, was once a cypress swamp – construction for the Metro unearthed remnants of bald cypress dating back 1000’s of years. And in both Baltimore and Philadelphia, ancient stumps and roots were found during construction in the 20th century. Divers discovered a submerged forest 60 feet underwater off the coast of Alabama that is over 50,000 years old (sea levels were lower during the last Ice Age, and that area was a coastal forest).
Because of its longevity, bald cypress tree ring data has been used to study rainfall and climatic history. This native American tree was prized in European gardens as early as 1640, and long used by Native Americans for canoes and houses. The naturalist John Bartram so prized the bald cypress that he planted it in his famous Philadelphia garden in 1730, and it was included in Bartram’s Catalogue of North American Plants.
Highly adaptable, bald cypress is equally at home in water or on dry land. It can survive inundation in fresh or brackish water, or in soils from heavy clay to sand. This long-lived prehistoric swamp giant is one of the few conifers that drop their leaves annually like deciduous trees do – hence its name. Its ferny, feather-like alternate leaves are yellow green in the Spring, turning soft green, gold, and bronze as the seasons progress. The dramatic foliage, along with the fluted and tapered trunks, buttressed at the bottom, make bald cypress easily identifiable.
If the tree is in a wet location and over 50 years old, it will have “knees” up to several feet tall protruding from the water. These were once thought to provide aeration for the roots, but recent research suggests otherwise; they are now thought to help the tree’s stability in water or muck. They disappear when the area is drained. Because its roots are able to withstand stress (growing in an oxygen-deprived environment without suffocation), bald cypress is also a successful street tree.
The seeds are eaten by small mammals and birds, and the high branches are nesting sites for herons, egrets, osprey, and eagles. Highly resistant to wind and ice load, the bald cypress prevents runoff and erosion, reduces flood damage, and filters water.
Until it is about 150 years old, a bald cypress has a pyramidal shape; after that the crown broadens. Male and female flowers appear on the same tree: In early Spring, purplish tassels 4-6 inches long appear. These are the male flowers. The female flowers are tiny green conelets at the base of the tassels, which become 1 inch round brown cones. The only way the tree propagates naturally is for the seeds to be spread by water.
In the swamps of the Southeast, bald cypress usually grows in pure stands – for the simple reason that there are few if any other trees that can grow in water, and so it has no competitors. Along with longleaf pine, old growth bald cypress is the most valued timber because the heartwood is rot resistant. Often called “the wood eternal”, it is in demand for boats, docks, siding, shingles, and mulch.
Bald cypress needs urgent protection: less than 1% of bald cypress forests have survived: swamps have been drained and the trees logged for timber or garden mulch. The remaining natural stands of cypress are sometimes, but not always protected. It is difficult or impossible to know whether cypress mulch comes from natural stands or commercial growers, so it is better to use wood chips or pine needles in your garden.
Two places to see old growth virgin bald cypress forests are the Audubon Corkscrew Swamp Sanctuary in Florida, where some trees are 150 feet tall and 1,000 years old. The other is the Nature Conservancy Black River Preserve in North Carolina, where a 2,600 year old tree is the oldest known living tree in the eastern US and the oldest known wetland tree in the world.
Meanwhile, you can come to the William Paca Garden (we will reopen in April!) to see our “young” (approximately 50 years old) bald cypress, with its knees poking up in and around the fish-shaped pond. But you don’t have to watch out for alligators; we don’t have any.
Dolores Dyson Engle
William Paca House and Garden Docent
