Many trees have delicate, finely divided foliage that resembles the fronds of a fern. This feathery appearance is visually appealing, but it can make identifying the specific tree species challenging. While true ferns are non-flowering plants that do not grow into trees, this common descriptive term points toward a specific leaf structure found across several distinct tree families.
Understanding Compound Leaves
The characteristic lacy appearance of these trees results from a leaf structure known as a compound leaf. Unlike a simple leaf, which has a single, undivided blade, a compound leaf is separated into individual segments called leaflets. These leaflets attach along a central stalk, or rachis, rather than directly to the main twig.
When leaflets are arranged directly along the central rachis, the leaf is described as pinnately compound, giving it a feather-like shape. The most finely divided, fern-like foliage comes from a bipinnately compound leaf, sometimes called double-compound. In this arrangement, the primary rachis branches into secondary stalks, and tiny leaflets attach along those secondary stalks. This multiple-level division gives the entire leaf a delicate, lace-like texture.
Highly Recognizable Ornamental Trees
Two frequently planted trees with this delicate foliage are the Mimosa and the Jacaranda, both prized for their ornamental qualities. The Mimosa, or Silk Tree (Albizia julibrissin), is easily identified by its unique summer flowers, which appear as showy, fluffy pink clusters resembling powder puffs. This small to medium-sized tree typically develops a broad, flat-topped, umbrella-like canopy. Its fruit are flat, straw-colored seed pods, measuring five to eight inches long, that persist into winter.
The Jacaranda (Jacaranda mimosifolia) is famous for its stunning display of lavender-blue flowers that cover the entire tree in late spring or early summer. These tubular blooms often drop to the ground, creating a temporary purple carpet beneath the tree. After flowering, the tree produces distinctive, round, flattened, woody seed capsules, about two inches in diameter. The Jacaranda’s crown is typically vase-shaped and open, making it a popular choice in warmer climates.
Hardy Landscape and Native Species
Other trees featuring fern-like leaves are larger, hardier species often integrated into municipal landscapes or found in native habitats. The Honeylocust (Gleditsia triacanthos) is a large, fast-growing deciduous tree that can reach heights of 80 to 100 feet. While many cultivated varieties are thornless, the native species possesses massive, branched thorns that can grow directly from the trunk and branches. It produces long, distinctive, twisting seed pods, sometimes over a foot in length.
The Kentucky Coffeetree (Gymnocladus dioicus) exhibits some of the largest bipinnately compound leaves in North America, sometimes measuring up to three feet long. This tree is one of the last to sprout leaves in the spring, and its winter appearance is marked by stout, coarse, and sparsely branched twigs. Female trees produce thick, leathery, dark reddish-brown seed pods, typically four to ten inches long, which often remain attached to the branches throughout the winter.