Slender Threeseed Mercury is a native, herbaceous, annual wildflower in the spurge family (Euphorbiaceae) typically found in the Eastern United States. The genus name is Greek and refers to the nettle-like shape of the leaves. The specific epithet is Latin for slender or graceful. Slender Threeseed Mercury is considered a weed and will grow just about anywhere, including sandy pinewoods, mixed forests, rocky outcrops as well as disturbed areas. The plant has a taproot that can grow deep in the soil, making it difficult to dislodge once established. A better strategy to avoid continuous weeding is to deadhead the flowers before seed is set or dig out the plant while it is still small. Slender Threeseed Mercury is a slender, upright plant that grows to a height between 1 and 3 feet depending on growing conditions. The stems are branched and green or reddish-brown. Fall color of the leaves is copper. Diseases, Insects, and Other Plant Problems: No significant problems. More information on Acalypha .
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) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Sand; Shallow Rocky
Soil drainage
Good Drainage | Occasionally Dry
Available space
12 inches-3 feet
Mature size
Height: 1 ft. 0 in. - 3 ft. 0 in. | Width: 1 ft. 0 in. - 3 ft. 0 in.
Growth rate
Medium
Maintenance
High
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect; Multi-stemmed
Texture
Medium
Leaf color
Brown/Copper; Green; Red/Burgundy
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Filiform; Oblong
Leaf margin
Serrate
Leaf feel
Smooth
Leaf value
Showy
Leaf size
1-3 inches long
Hairs present
No
Leaf detail
The leaves are set alternately on the stem, very narrow and between one and two inches long. They are a bright green color turning reddish copper in the autumn.
Fall color
Brown/Copper
Flower color
Gold/Yellow; Green; White
Flower form
Insignificant; Raceme; Spike
Flower shape
Crown
Flower size
< 1 inch
Flower detail
Insignificant half inch flowers, but colorful bracts that bloom mid-spring. The flowers are carried in the axils of the leaves, (that is, the point where the leaf emerges from the stem). The plant produces female and male flowers held on a raceme less than half an inch long. The female flower, at the base, has tiny, bright green bracts with serrated edges and translucent 'hairs' at the base of the pistil. It is only after pollination has occurred that the flowers become more obvious. The male flowers are held at the end of the raceme in a tight cluster of many flowers around a quarter of an inch long. They have white to golden yellow petals.
Bloom time
Fall; Spring; Summer
Fruit color
Brown/Copper; Red/Burgundy
Fruit type
Capsule
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruit is less than an inch around. Each female flower has the capacity to produce three seeds if well pollinated. There is one variety, monococca, which produces only one seed. After pollination, a small, three lobed 'crown' develops with a seed in each developed lobe. The plant is air pollinated.
Stem color
Brown/Copper; Green; Red/Burgundy
Stem detail
The stem is slender and usually straight with branching. It carries small hairs along its entire length. The color can vary from green to reddish-brown.
Wildlife & Ecology
Native status
Native
Origin
Central and eastern United States.
Distribution
AL , AR , CT , DC , DE , FL , GA , IA , IL , IN , KY , LA , MA , MD , ME , MI , MO , MS , NC , NH , NJ , NY , OH , OK , PA , RI , SC , TN , TX , VA , VT , WI , WV