Edward F. Gilman, Dennis G. Watson, Ryan W. Klein, Andrew K. Koeser, Deborah R. Hilbert, and Drew C. McLean
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Introduction
Similar to baldcypress in that the trunk is perfectly straight 50 to 60 feet tall, pondcypress has a narrower crown, is smaller, and has a more open habit. It is found along the edges of streams and around the edge of swampy ground where water is standing; whereas baldcypress is usually found along stream banks. The bright green, awl-shaped leaves are arranged in an upright row formation along the branches when young, giving a somewhat stiffer and more upright appearance than baldcypress. The leaves turn an attractive light brown in fall before dropping but the bare branches and light brown, ridged bark provide much landscape interest during the winter. The trunk grows unusually thick toward the base, even on young trees. This is thought to provide support for the tree in its wet habitat. The small seeds are used by some birds and squirrels.
Figure 1. Full Form—Taxodium ascendens: pondcypress
General Information
Scientific name: Taxodium ascendens
Pronunciation: tack-SO-dee-um uh-SEN-denz
Common name(s): Pondcypress
Family: Cupressaceae
USDA hardiness zones: 5B through 9B (Figure 2)
Origin: native to the southeastern United States
UF/IFAS Invasive Assessment Status: native
Uses: sidewalk cutout (tree pit); tree lawn 3–4 feet wide; tree lawn 4-6 feet wide; tree lawn > 6 ft wide; street without sidewalk; specimen; reclamation; parking lot island < 100 sq ft; parking lot island 100–200 sq ft; parking lot island > 200 sq ft
Although often seen at water's edge where it will develop "knees", or root projections, that will extend above the water for gas exchange, pondcypress can also be grown in dry locations and could make an attractive street tree for a very narrow space. Cypress knees do not generally form on these drier sites. The "knees" do not form as readily as on baldcypress, even on wet sites. It provides a good vertical accent to the landscape and should be used more often in urban areas. The roots do not appear to lift sidewalks and curbs as readily as some other species. Its delicate foliage affords light, dappled shade, and the heartwood is quite strong and resistant to rot. However, most lumber available at lumber yards today is sapwood and is not resistant to rot.
Pondcypress is ideal for wet locations, such as its native habitat of stream banks and mucky soils, but the trees will also grow quite well on almost any soil, including clay, silt, and sand, except alkaline soils with a pH above 7.5. Its drought-avoidance mechanism allows it to drop leaves in extended dry periods but little harm appears to come to the tree. Pondcypress is relatively maintenance-free, requiring pruning only to remove dead wood and unwanted lower branches which persist on the tree. It maintains a desirably straight trunk without pruning and does not form double or multiple leaders as do many large trees.
The cultivar 'Prairie Sentinel' is narrower than the species.
Propagation is by seed.
Diseases
No diseases are serious.
Twig blight is caused by a weak pathogen and is usually present on dead or dying tissue. When the tree is stressed the fungus can kill branch tips. Dead tips can be pruned off. Do not let dead or diseased branches remain on the tree. Keep trees healthy with regular fertilization.
Reference
Koeser, A. K., Hasing, G., Friedman, M. H., and Irving, R. B. 2015. Trees: North & Central Florida. Gainesville: University of Florida Institute of Food and Agricultural Sciences.
