|Natural range of the water elm|
Planera is a genus of flowering plants with a single species, Planera aquatica, the planertree or water elm. Found in the southeastern United States, it is a small deciduous tree 10–15 m tall, closely related to the elms but with a softly, prickly nut 10–15 mm diameter, instead of a winged seed. It grows, as the name suggests, on wet sites. Despite its common English name, this species is not a true elm, although it is a close relative of the elms (species of the genus Ulmus). It is also subject to Dutch elm disease, a disease which affects only members of the Ulmaceae. It is native to most of the southeast United States. It is hardy down to Zone 7.
- Leaves: alternate, 3–7 cm long, with irregularly serrated to double serrated margins. Leaf base wedge-shaped or rounded. Leaf base often equal and symmetrical, but can be asymmetrical. Thin pubescent hair is often present on underside of leaf.
- Bark: gray-brown, thin, some flaky loose scales. Exfoliates to reveal red-brown area under bark.
- Fruit: a drupe. Has a green shell that turns brown with age. Matures April - May.
While often confused with true elms, it can be easily distinguished by noticing the fruit are drupes and not samaras. When fruit are not in season, the flaky bark is unique to water elm and not characteristic of true elms.
Typically found on alluvial floodplains subjected to seasonal or temporary flooding. Often found in swamps, streams, lakes, or in riparian areas. Has some wildlife value, food for bees and some bird species. Prefers sandy or gravelly, moist soils.
- IUCN SSC Global Tree Specialist Group.; Botanic Gardens Conservation International; et al. (BGCI) (2020). "Planera aquatica". IUCN Red List of Threatened Species. 2020: e.T152858603A152905699. doi:10.2305/IUCN.UK.2020-1.RLTS.T152858603A152905699.en. Retrieved 12 April 2020.
- "Search results for Planera". The Plant List. Retrieved 1 March 2016.
- "Planera aquatica". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 7 October 2015.
- "Water Elm Ulmaceae Planera aquatica J.F. Gmel". Virginia Tech Department of Forestry and Environmental Conservation. Retrieved December 15, 2014.
- Kirkman, L. Katherine. (2007). Native trees of the Southeast. Brown, Claud L., 1925-, Leopold, Donald Joseph, 1956-. Portland, Or.: Timber Press. ISBN 978-0-88192-828-0. OCLC 69792028.
- "Planera aquatica (Water Elm) | North Carolina Extension Gardener Plant Toolbox". plants.ces.ncsu.edu. Retrieved 2020-11-02.