Thryallis is a small evergreen tropical shrub that grows to a maximum height of about 6 ft and about as wide. It grows moderately fast into a neat rounded shape with many slender stems that are reddish when young. This shrub forms a dense and twiggy mass covered in light green oblong leaves. These are arranged oppositely and are 1-2 in long and take on bronze tones during cooler periods. Thryallis smothers itself in beautiful yellow blossoms in late summer and fall although some flowers can be expected at all times if warm temperatures are maintained. The yellow flowers are about 3/4 in in diameter and are held in 4-6 in clusters at the stem tips. Flowers are followed by interesting three part seed capsules.