Plant Profile: Phyllanthus urinaria

Chamberbitter is a summer annual characterized by its heavily branched base and upright stems, typically reaching heights of 1 to 2 feet and often forming a mound. The leaves are oblong, measuring between 1/2 to 3/4 inch long, and are found on short branches, resembling the compound leaves of certain legumes. Despite belonging to the spurge family, chamberbitter does not release a milky sap when its stems are broken. The flowers are small, subtle, and greenish-white in color. Notably, the round fruit appears on the undersides of lateral branches at the leaf axils. While it shares a resemblance with long-stalked phyllanthus (Phyllanthus tenellus), the two can be distinguished by the length of their seedpod stalks: chamberbitter's fruit is sessile (lacking stalks), whereas long-stalked phyllanthus has stalks measuring approximately 1/4 to 1/2 inch. Phyllanthus seeds require substrate temperatures exceeding 75°F for germination, making them more prevalent in summer, although they can persist into late fall in the southeastern United States and year-round in subtropical regions. These plants bloom throughout the summer and fall, ultimately dying off after frost, with their fruit forcefully ejecting seeds over short distances.

Management strategies for chamberbitter: Both phyllanthus species are notoriously challenging to control. It is crucial to prevent the plants from seeding. Before planting, thoroughly inspect pots to eliminate any new infestations before they can spread. Most preemergence herbicides labeled for use are ineffective against them.

Propagation: Seeds are expelled forcefully.