A native tree that wouldn’t look out of place on a windy mountaintop, buttonwood grows with twists and turns and gnarls that make it look like an ancient windswept sentinel.
Buttonwood (Conocarpus erectus) is also called button mangrove, which gives you a clue that it is naturally found near shorelines and has no problem with brackish water and salt spray. It is found throughout much of the subtropics and tropics of the Americas and, surprisingly, parts of western Africa. If you look at a map of its Florida distribution, it fringes our coasts along most of the peninsula.
But this presents a fascinating problem: How does the same species of plant grow in places as far-flung as Africa and Florida? Either they grew in such places before the continents drifted apart, or the globe-shaped fruit, dispersed by water, floated over from one place to the other. Or maybe someone planted them. Can someone please research this and report back to me?
If you searched only coastlines for buttonwood, you’d miss out, because it is also a common street and parking lot tree and seems to do perfectly fine away from any shore or coast.
Given its druthers, it seems to prefer the brackish, silty, muddy shores of the mangrove zone and the company of actual mangrove plants, with red mangrove (Rhizophora mangle) in the water backed by black mangrove (Avicennia germinans), with buttonwood and white mangrove (Laguncularia racemosa) both at slightly higher elevations. Those last two are also the most sensitive to cold. Think of white mangrove and buttonwood as lazy tourists: They like the sun and sand and beach views, but don’t really want to swim.
There are two color varieties, green and silver buttonwood. Some sources give each a variety name after the genus and specific epithet; I consider my source reliable and it does not consider them true varieties.
The silver version’s foliage is certainly grayish silver compared to the green buttonwood, or rather just buttonwood. The silver is also generally a shorter, bushier plant.
Both types seem to lean, and they root where the leaning trunks contact the ground. And trunks is plural for both: Buttonwood is multi-stemmed, but can be grown with a single trunk.
Even younger trees produce deeply furrowed grayish-brown bark, and the trunk seems to twist and bend. They look very old, wizened and weathered, probably one reason they are popular bonsai trees.
The flowers are small and inconspicuous to our eyes, and are followed by fruit that is cone-like. Conocarpus means “cone seed” or “cone fruit.”
Buttonwood is a nectar source and larval host plant for the martial scrub hairstreak butterfly (Strymon martialis) and tantalus sphinx moth (Aellopos tantalus), and serves as an essential home for epiphytes like Tillandsia and orchids. Find a buttonwood and you’ll likely find orchids within its gnarled bark.
For coastal gardening, they make excellent specimen plantings or hedges, with great resistance to salt spray and some resistance to salt water inundation.
Buttonwood — either color — tolerates drought, inundation, pollution, compact soil, sandy low-nutrient soil, salt, and does well in high wind. It only asks for direct sun and warmth.
Though the green version is a taller tree, neither buttonwood is likely to get massive, and like other mangrove plants is likely to get wider than it is tall. Check out the profoundly gnarled and twisted champion buttonwood in Key West, measured at 35 feet tall with a 70-foot crown spread.