Chamberbitter is a flowering summer annual, native to Asia, in the polkweed family. It is heavily branched at the base with ascending stems, often forming a mound 1 to 2 feet in height. Leaves are oblong in shape, 1/2 to 3/4 inch in length, on short branches, and look similar to compound leaves of some legumes. Unlike other weeds in this family, chamberbitter stems do not exude a milky sap when broken. Flowers are small, inconspicuous, and greenish-white. Distinctive round fruit are borne on the undersides of the lateral branches at the leaf axils. The plant requires warm soil and full sun. The large amount of seeds produced and the extensive root system of this plant make it very competitive with other nearby plants. Similar in appearance to long-stalked phyllanthus ( Phyllanthus tenellus ), the two species differ by the length of the seedpod stalks. Chamberbitter fruit are borne sessile (without stalks) whereas long-stalked phyllanthus stalks are about 1/4 to 1/2 inch long. Phyllanthus require substrate temperatures above 75 degrees F to germinate and thus are more common in the summer, but will persist into late fall in the southeastern US (and year-round in sub-tropical areas). Plants flower throughout the summer and fall then die after frost. Fruit forcefully expel seed short distances. Chamberbitter is listed as an invasive species in Alabama. The Clemson University Home and Garden Information Center has an factsheet on mechanical and chemical controls of this weed. Insects, Diseases, and Other Plant Problems: Both species of Phyllanthus are particularly difficult to manage. Do not let plants go to seed. Inspect pots before planting and eradicate new infestations before they can spread. They are poorly managed by most preemergent herbicides labeled for use.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day)
NC region
Coastal; Mountains; Piedmont
Growth rate
Medium
Maintenance
High
Canopy layer
3 - Shrub
Form & Appearance
Habit / form
Erect; Mounding; Spreading
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Linear; Oblong
Leaf margin
Entire
Leaf size
< 1 inch long, < 1 inch wide
Hairs present
No
Leaf detail
Tiny (0.2" long 0.2") wide alternate bright dark green above reddish green below. The leaves close and night and open during the day.
Flower color
Gold/Yellow; Green; White
Flower form
Insignificant
Flower size
< 1 inch
Flower detail
Insignificant small greenish-yellow-white male and female flowers on same plant. Female flowers form from the first to middle part of the leaf and male flowers from the middle to the tip.
Fruit color
Green; Red/Burgundy
Fruit size
< 1 inch long
Fruit detail
Green or greenish red .12" in diameter divided into three parts. The surface has scales that are raised and when it dries it expel seeds for dispersal.
Stem color
Red/Burgundy
Stem detail
Branching slender stems are crimson red.
Wildlife & Ecology
Native status
Non-native
Origin
Tropical & Subtropical Asia to N. Australia
Distribution
Southeastern United States, Central America, Northern South America, Central Africa