Bald Cypress Trees: Thirsty for Soggy Soils

Many homeowners are plagued by soggy or low-lying wet areas which seemingly transform suburban backyards into Cajun-friendly bayous. Poor drainage, heavy soils, and excessive runoff from neighboring yards or roadways can make it almost impossible to grow much more than moss and alligators. One solution to this swampy situation might be found in the bald cypress, a fast-growing, bog-friendly tree which not only thrives in moist environments, but can also sponge up and transpire many hundreds of gallons of water a day!

The bald cypress (Taxodium distichum), also called swamp cypress or southern cypress, is not a true cypress at all but is actually in the same plant family as the sequoias or giant redwoods, and shares some of its Western relation’s fabled characteristics, such as longevity, living 800 to 1500 years, and height, with mature specimens reaching well over 100 feet.

The “bald” in the tree’s common name relates to the fact that while it is a conifer, like pines or cedars, it is unlike those evergreens as it sheds its needles in autumn. This characteristic makes it attractive when landscaping to shade the side of a house in summer, while allowing warming sunlight through in the winter.

Another attractive element is the progression of color in the tree’s foliage. In early spring, the horizontal branches will send out short, flat, feathery needles that are a bright yellowish-green. Entering summer, the needles become somewhat duller and sage green, until fall when the needles take on a pale orange or russet tone, until finally turning brown and dropping.

Besides its deciduous nature, the bald cypress is best known for the “knees” which emerge like conical projections through the soil at various distances from the trunk, typically in the wettest soil areas, such as the zone between the tree and a pond or stream. These knees are believed to help stabilize the tree in soft wet or muddy soils, although there is some conjecture that the knees also help in the exchange of oxygen and carbon dioxide for constantly submerged roots.

A quick visit to the boardwalk and freshwater marsh of Theodore Roosevelt Island, located opposite the Kennedy Center in Washington, D.C., will bring you within petting distance of a dozen or so medium-sized trees ringed round with knobby brownish-red knees.

Of course, the bald cypress is actually native to (and undoubtedly symbolic of) the coastal plains and swamps of the Southeast. It would be hard to imagine the ghostly swamps and bayous of Louisiana -- where it is the state tree -- or even the Florida Everglades, without picturing the buttressed trunks and somber, lichen-covered boughs of the bald cypress, “bearded with moss,” as Longfellow depicted the forest primeval in his famous 1847 poem Evangeline.

Interestingly, while the term “cypress swamp” inevitably conjures images of Spanish moss, still black water, and steamy, Arcadian locales, the bald cypress includes Maryland and Delaware as part of its natural range, as you will find in the Great Cypress Swamp on the Delmarva Peninsula. The species also spreads as far west as Illinois and Indiana. Further to the north, where it grown primarily as an ornamental tree, it has found a welcome home in the not-so-sultry environs of Minnesota and upstate New York.

The appeal of the bald cypress has a broad range as well: natural resource managers favor it for riparian plantings and wetland restoration projects, landscape designers appreciate its elegant adaptability to the wettest of conditions, and gardeners simply love the tree’s natural beauty and majesty, whether planted singly as a specimen tree, or planted in smaller, managed groves beside community ponds.

Naturalists, weekend birders, and hunters are drawn to stands of bald cypress for the habitat they represent, which supports numerous songbirds, turkeys, wood ducks and other waterfowl. Overhead, the upper canopy provides nesting areas for herons, storks, egrets, as well as raptors, such as eagles and osprey. The supportive buttresses of the tree trunks and storied “knees” of the root structures also host populations of rare tree frogs and salamanders, while the murky waters below provide habitat for aquatic organisms as diverse as jumpin’ catfish and ‘gators.

For centuries, bald cypress has been used extensively in a variety of commercial applications thanks to the wood’s natural resistance to rot and decay. After all, if the tree can comfortably sit in water all day for centuries, what difference can it make to spend a few decades as a piling for a marina?

Often referred to as the “wood eternal,” it was used for fence posts, docks, boat hulls, shingles, shakes, and any other location where soil contact, weather and water might contribute to decay. Even the shredded outer bark is sort after as a long-lasting garden mulch or planting medium for orchids.

Regrettably, harvesting was conducted well beyond sustainable limits, and the once vast cypress groves have disappeared, save for protected areas and nature preserves. In fact, it has been noted that the bald cypress suffered the worst reduction in volume of any tree during the twentieth century, with the exception of the blight-ravaged American chestnut.

Yet while the cypress swamps are a shadow of their former selves, there are plenty of opportunities for planting and enjoying this magnificent and versatile tree. And what’s not to love?

The tree remains relatively pest-free, requires no fertilizing or pruning, and grows amazingly quickly with little encouragement: up to two or three feet per year, although some cultivated and named varieties grow more slowly. In fact, a new Dutch dwarf variety called Peve Minaret will provide a compact eight-foot specimen more suited for use as a large shrub along a foundation or entranceway.

Finally, while a bald cypress can easily handle all the wet weather and runoff your yard can throw at it, and even possibly transpire a lot of unwanted wetness away, this incredible tree is also quite comfortable on dry sites, from the middle of a sunny yard, to alongside a hot, busy street. Of course, without wet soils, you will never find cypress knees popping up unexpectedly in your lawn or driveway, but that might actually be for the best.

Copyright 2009, Joseph M. Keyser