Brief Intro: I was blog surfing UF/IFAS a while back and found an interesting article by Broward Education/Specialist Donna Corbelli Castro. It was titled “A Nearly Perfect Tree.” Well, if that doesn’t attract the attention of a FUFC member, nothing will. It was my first introduction to Black Ironwood (Krugiodendron ferreum) (krug-ee-oh-DEN-dron krug-ee-oh-DEN-dron). Literally, it means Krug’s Tree Iron. It was named for Carl Wilhelm Leopold Krug (1833- 1898), German consul in Puerto Rico, businessman, botanist, and science patron. Ferreum means iron and refers to the tree’s resistance to decay and its density. Black Ironwood is also called Leadwood because when it is cut, the aroma given off is nearly identical to the smell of molten lead.
Black ironwood is found throughout the more rural Caribbean, where it is still used for tools and for making weapons, such as bows, arrows, and lances. Its density gives it a high polish and is favored by turners. Ironwood appears in maritime hammocks, on raised coastal areas, where the climate is strongly moderated by proximity to the ocean. As a result, these hammocks often support vegetation that appears more tropical than that of similar hammocks farther inland. Soils are typically sandy, and fire is rare or absent. The canopy is usually a mixed hardwood forest.
Black ironwood requires very little structural pruning, is long-lived, evergreen, and rarely sheds its leaves (even in a cold snap). Ironwood is a strong, tidy, and nearly perfect tree.
Habitat: Ironwood is suitable for zones 10A, 10B and 11, an area encompassing much of central and south Florida, throughout the Caribbean, and from southern Mexico to Honduras. It is an important canopy or subcanopy tree in hammocks. Black ironwood resists disease and termites. Despite growing in coastal areas, it has a low saltwater tolerance and does not tolerate long-term flooding by salt or brackish water. It is moderately tolerant of salt wind. It is beneficial to protect it from direct salt spray with other vegetation. Try mixing with other coastal hammock species like Gumbo Limbo, Paradise Tree, Lancewood, the Stoppers, Inkwood, Crabwood, or any of the other coastal species.
Back ironwood has moderate to high nutritional requirements and grows best with some organic content. It may languish in nutrient-poor soils. Ironwood will grow in almost any area, from occasionally wet to very dry, in full sun to part shade.
Form: Black ironwood typically grows to 25–35 (30) ft. but sometimes grows as a shrub.
Photo by T. Ann Williams
Leaves: Black ironwood is considered evergreen. Its leathery leaves are always shiny and provide shelter and food for birds and shade for humans.
Photo by John R. Park
Bark: Dark brown to blackish, rough, and scaly. The sapwood is light brown, streaked, with the heartwood orange-brown to dark brown.
Flowers: Black ironwood flowers are greenish-white with inconspicuous blooms in spring, but the small flowers secrete copious amounts of nectar.
Fruit: The fruit is a purplish-red to black oval or nearly round, 1/3” long drupe and ripens in fall-winter. The fruit looks similar to dark M&Ms. The fruit is edible, sweet, and provides moderate amounts of food for wildlife. The fruit can be used for jam, jelly, wine, and eaten raw out of hand. Not the greatest and not the worst. They dry before falling, so are not messy.
Urban Forestry: Black ironwood is suited to our increasingly populated urban areas of Florida, and specifically Central and South Florida. Black ironwood is best used as an accent or specimen tree in residential and commercial landscapes. It can be slow-growing and sometimes difficult to establish. Ironwood will rarely outgrow an area or lift pavement.
Photo and © by Roger Hammer, Wildflowers of the Everglades
Little Known Facts:
The wood is hard, the densest of all woods native to South Florida. It will sink in water.
Credits
- Florida Native Plant Society
- Donna Corbelli Castro, UF/IFAS, A Nearly Perfect Tree
- Natives for your Neighborhood
- Eat the Weeds
- Meadow Beauty Nursery
- Photos – Atlas of Florida Plants – USF Libraries T. Ann Williams Photographer
