Virginia Tech Weed Identification Guide

Wild Four-O' Clock: Mirablis nyctaginea

Weed Description:  Erect perennials with tuberous thickened roots that may reach 4 1/2 feet in height.  Wild four-o' clock is primarily a weed of pastures, hay fields, roadsides, and abandoned locations that is found in North Carolina, Kentucky, Virginia, and West Virginia.

Roots:  Very thick and tuber-like in some places.

Stems:  Plants usually range from 1 1/2 to 4 1/2 feet in height.  Stems are erect and branching.

Leaves:  Leaves are triangular to triangular-lanceolate in outline, from 1 1/2 to 3 inches long and 1 to 2 inches wide.   Leaves occur on petioles that are approximately 3/4 inch or less in length.   Leaves have a deep green color and have prominent white midveins.

Flowers:  Flowers are pink to lavender in color and occur on flower stalks (peduncles) that range from 3 to 10 mm in length.

Fruit:  A gray or brown achene that is 4 to 5 mm long and elliptical.

Identifying Characteristics: Plants with thick rootstocks and triangular leaves that are dark green in color with prominent white midveins.