Japanese angelica tree features impressive tripinnately compound leaves, spanning 2 to 4 feet (60 to 120 cm) in length, comprising up to 80 leaflets. Each leaflet measures 3 to 5.5 inches (7.5 to 14 cm) and can have either toothed or smooth margins. Prominent center veins extend to the tips, and spines are present in the leaf axis. The leaves exhibit a vibrant fall color, transitioning from yellow to reddish-purple, making them a striking characteristic of japanese angelica tree.

The flowers of japanese angelica tree display in large panicles measuring about 12 to 18 inches (30 to 45 cm) in length. These blossoms are white to cream in color, forming dense clusters that span wider than they are tall. They bloom from late July to August, creating a striking visual display. The flowers are small, with numerous petals arranged in a symmetrical pattern, offering a delicate and airy appearance. Their blooming period highlights the mid to late summer garden with subtle, yet elegant charm.

The stem of japanese angelica tree is characterized by its thick, robust structure, typically ranging from 2 to 3 inches (5 to 7 cm) in diameter, with a dark brown to gray coloration. One of the most distinguishing features is the presence of large, sharp spines that can grow up to 1 inch (2.5 cm) long, making the stem notably prickly. The stem surface is rough to the touch, and it exhibits a branching pattern where large, arching branches form at intervals along the main stem.

The fruit of japanese angelica tree is a small, spherical drupe measuring about 0.2 inches (5 mm) in diameter. Initially, the fruits present a purple hue, gradually deepening to an almost black color as they mature through summer into autumn. Each fruit contains multiple tiny seeds encased within a fleshy outer layer. The surface of the fruit is smooth, with a subtle shine that makes them noticeable among the foliage. They are often found in dense clusters at the ends of the branches, providing a striking visual contrast against the green leaves.