Virginia Tech Weed Identification Guide

Tropic Croton: Croton glandulosus var. septentrionalis

Weed Description:  Summer annual weed that ranges from 4 to 20 inches in height and is a problematic weed of many agronomic crops in the southeastern United States like corn, soybeans, cotton, and peanuts.  Tropic croton may be found throughout the southeastern United States.
Seedling: Stems below the cotyledons (hypocotyls) are covered with hairs that take on a star-shaped appearance.  Cotyledons are thick, heart-shaped, 5 to 7 mm long by 7 to 10 mm wide, and have three distinct veins that originate from the same point (palmate venation).  First true leaves are round to oval in outline and have margins that are toothed.
Leaves:   Alternate, oval in outline when young, lance-shaped to elliptic in outline with maturity, approximately to 2 inches long, and have margins that are sharply serrated or toothed.  Leaves occur on short petioles and have a white, disc-like gland on each side of the petiole where the petioles attach to the central stem.  Leaves that occur below flowers appear whorled and upper and lower leaf surfaces have hairs that take on a star-shaped appearance.  Leaves emit a distinctive odor when crushed.
Stems:   Branching, becoming reddish brown with age, and covered with hairs.

Roots:  A taproot.

Flowers:  Terminal white flowers that are approximately inch long occur at the ends of stems.

Fruit:   A brown capsule.

Identifying Characteristics: Summer annual with serrated leaves and white, disc-like glands that occur above and below the petiole at the point of attachment to the stem.  Tropic croton is sometimes confused with Eclipta (Eclipta prostrata), however the leaves of eclipta are much more linear in outline and are arranged oppositely along the stem unlike the alternate leaves of tropic croton.  Prickly Sida or Teaweed (Sida spinosa) also resembles tropic croton in growth habit and appearance, however prickly sida has linear stipules at the base of the petiole but lacks the disc-like gland that occurs on tropic croton.   Additionally, the stems of tropic croton are much more hairy than those of prickly sida.