Fraxinus profunda aka Pumpkin Ash

Fraxinus profunda, or pumpkin ash, belongs to the olive family. This deciduous tree comes from central and eastern North America. Its range reaches from New York to Missouri, then south. It extends to Florida and Louisiana and includes eastern Canada. It grows in swamps, floodplains, river valleys, and other low ground. Bald cypress often shares these wet sites with it.

Garden trees reach 60–80 feet [18–24 metres] tall. Their crowns spread 30–50 feet [9–15 metres] wide. Some trees reach 125 feet [38 metres], beyond the usual range. The RHS gives a smaller spread of 13–26 feet [4–8 metres]. The crown is open, and growth proceeds at a moderate rate. In flooded ground, the trunk base may swell. This pumpkin-like shape offers one explanation for the common name. The tree needs ample room to reach its full size.

The bark is pale gray-brown, with crossing ridges and block-like patches. Stout young twigs bear fine hairs and rough brown buds. Leaves grow in opposite pairs and have seven to nine leaflets. Each large, pinnate leaf has a firm, leathery feel. The green leaflets have pale, hairy undersides. Fall shades include bronze, red, and purple before leaves drop. Small green to purple-green flowers form clusters in April and May. Most trees bear either male or female flowers. Female trees carry hanging groups of flat, single-winged samaras. These fruits turn from green to brown as they mature. They ripen from late summer into early fall.

Plant it in full sun with soil that stays moist. It also tolerates light shade, but cannot cope with dry soil. Suitable soils include clay, loam, and sand. Wet sites suit it, including ground with poor drainage. The RHS lists neutral to alkaline soil conditions. Sources place it in USDA zones 5–9 and UK rating H7. Seed offers a means of propagation. Its size suits large native gardens, woodland areas, and wet landscapes. It also serves as a host for moth caterpillars.

Emerald ash borer makes new planting a poor choice. Infested trees often die within three to five years. Other pests include lilac borers and carpenter worms. Leaf spots, mildew, rust, and cankers can also occur. The RHS notes risks from ash dieback and honey fungus. Brittle limbs can break in strong winds.