Plant Details

Coleus amboinicus is a rapid growing, branched, evergreen, ascending, spreading shrublet, 300–700 mm tall. The roots are fibrous. All parts are highly and pleasantly aromatic. The stems are ascending spreading (decumbent) and up to 1.5 m long, succulent, almost rounded to somewhat 4-angled, green when young and about 4 mm in diameter, the mature stems becoming brownish and about 7 mm in diameter. The stem surface is covered in dense, whitish, translucent, long and short, multicellular hairs. The internodes are 5–55 mm apart, depending on the growing conditions. Leaves are brittle, broadly egg-shaped to triangularly egg-shaped (ovate) with a short petiole 8–20 mm long; the blade is 35–50 mm long and 25–47 mm in diameter. When grown under exposed, sunny, dry conditions, the leaves are shorter and folded in (conduplicate), however, in shady, moist conditions the leaves tend to be flattened and only slightly concave. The margin with about 12 pairs of shallow pointed teeth. The base of the leaf is truncate and the tip (apex) acute to almost rounded. The surface is covered in tiny, translucent to brownish gland dots and is very hairy, especially on the conspicuous network of veins on the lower surface. The inflorescence is a terminal raceme, 100 to 500 mm long; the flowers are arranged in whorls of 4–10, each flower 7–9 mm long, white to mauve and slightly deflexed, expanding to the throat. The calyx is 2–3 mm long, elongating to 5–6 mm when mature. The seed is a light to dark brown, slightly flattened nutlet, 1 mm across. Flowering time is late summer to autumn, the seeds released in winter and spring. In cultivation, and especially the tropics, it can flower at other times of the year.