Pink family (Caryophyllaceae)
Description: This adventive perennial plant is 1–2½' tall, branching occasionally. The stems are erect or spreading, and more or less hairy. The opposite leaves are up to 2" long and 1" across. They are cordate-ovate, smooth along the margins, slightly pubescent, and usually sessile (the lower leaves may have short petioles). Single flowers may develop from the leaf axils of the upper stems, while the remaining flowers occur in small clusters at the end of stems.
Each flower is about ½" across when it is fully open, consisting of 5 white petals that are cleft, 5 green sepals that are ovate and pubescent, 5 slender white styles, and 10 stamens. There is some variability across populations of plants regarding how deeply cleft the petals are. These petals are slightly longer to much longer than the sepals. The pedicel of each flower is conspicuously pubescent and up to 1" long. The blooming period occurs from late spring to late summer and lasts about 2-3 months. Each flower is replaced by a seed capsule that is ovoid and single-celled; it contains several seeds. Each seed is orbicular-reniform and minutely bumpy across the surface. The root system is fibrous and produces rhizomes, which enables this plant to form vegetative colonies.
Cultivation: The preference is full sun to light shade, wet to moist conditions, and fertile soil that is loamy or silty. It can withstand dry conditions for short periods of time.
Range & Habitat: Water Chickweed occurs occasionally in northern Illinois and a few counties in central Illinois (see Distribution Map). It is adventive from Europe and appears to be spreading. Habitats include wet to moist areas along streams, meadows, roadside ditches, pastures, and gardens. It often occurs in degraded habitats, but can also be found in higher quality habitats growing alongside native flora.
Faunal Associations: The nectar of the flowers attracts small bees and Syrphid flies; some bees may collect pollen, while flies occasionally feed on pollen. The caterpillars of several moth species probably feed on the foliage, like other chickweeds. The seeds of chickweeds are attractive to sparrows and other birds, while the foliage is eaten by rabbits. Because Water Chickweed frequently occurs in wetland habitats, its foliage is probably eaten by the Canada Goose.
Photographic Location: The photographed plant was growing in a large flower pot at the webmaster's apartment complex in Urbana, Illinois. Water Chickweed also occurs along streams and drainage ditches in the area.
Common: This is the largest chickweed in Illinois and one of the more attractive species in this group of plants. It can be combined with other flowering plants to good effect in a flower garden. However it may be regarded horticulturally, ecologists regard this species as a weed because it is non-native. The identification of different Chickweed species is difficult. Water Chickweed belongs to a group of Chickweeds that has flowers with 5 styles and 10 stamens. However, Water Chickweed has larger flowers and leaves than other members of this group (mainly Cerastium spp.). It resembles Stellaria pubera (Starry Chickweed) somewhat, but the latter has flowers with 3 styles and leaves that are more narrow at the base. Both of these species share the common name 'Giant Chickweed.'