In the river swamps of northwest Florida, the first tree to come to mind is typically the cypress. The “knees” protruding from the water are eye-catching and somewhat mysterious. Sweet bay magnolia is an easily recognizable species as well, with its silvery leaves twisting in the wind. The sweet bay (Magnolia virginiana) is a relative of the Southern magnolia (Magnolia grandiflora) in many of our yards, but its buds and leaves are smaller and it is found most often in very wet soils.
However, the often-unsung trees of the swamps are the tupelo and blackgum trees, including three species of Nyssa that go by a variety of overlapping common names. In the western Panhandle, one is most likely to see a swamp tupelo/swamp blackgum (Nyssa sylvatica var. biflora). The trees are tall—60-100’ at maturity—and have unremarkable elliptical green leaves. However, those leaves turn a lovely shade of red in the fall before dropping in the winter. Their most distinguishing characteristic year-round–but especially in the winter–is its swollen lower trunk, which expands at the base to twice or three times the size of the remaining trunk. These buttresses, also found on bays (more subtly) and cypress (along with knees), are an adaptation to stabilizing a tree growing in large pools of wet, loose soil or standing water.
The swamp tupelo has two more relatives in the region, water tupelo (Nyssa aquatica) and Ogeechee lime/tupelo (Nyssa ogeche), both with hanging edible (but tart) fruit. In the early days of William Bartram’s explorations of Florida, explorers used the acidic Ogeechee lime as a citrus substitute. Typically found in a narrower range from Leon County east to southeast Georgia, the Ogeechee lime is the nectar source for the famous and prized multi-million dollar tupelo honey industry.
Blackgum or tupelo trees (missing the “swamp” in front of their common name—aka Nyssa sylvatica) are actually excellent landscape trees that can thrive in home landscapes. Like their swamp cousins, the trees perform well in slightly acidic and moist soil, although they can thrive even in the disturbed, clay-based soils found in many residential developments. Blackgums can grow in full sun or shade, are highly drought tolerant, and can even handle some salt exposure. Their showy fall color is a nice addition to many landscapes, and the fruit are an excellent source of nutrition for native wildlife.