The uniquely shaped flowers of biennial guara have an exceptionally long bloom time, from June through October. Erect, wiry, sparsely leaved stems are topped by many delicate, whitish-pink flowers that open in the evening. It has a slightly weedy appearance and often looks best when used for naturalizing or as part of pollinator or native gardens. It's also useful as a screen or back-of-the-border plant. Unlike the popular cultivar that is a petite 2 or 3 feet in height, this native can grow over 6 feet tall, and the red-tinged stems add color throughout the season. Also known as beeblossom, it is a pollinator magnet, drawing in hummingbirds and many species of bees, butterflies, and moths. It prefers full or part sun and can handle poor, occasionally dry conditions in a wide range of soils. It also fares well in moist soils.
Because it's a biennial (two-year life cycle), only dense, flat rosettes of green leaves will appear the first year. During the second year, the plant will shoot up 4 to 6 feet with airy arrays of flowers. Its self-seeding habit helps to ensure that future plants will take root. After the first flush, if plants are cut back assertively, they will produce a second flush of blooms.
Native habitats include disturbed soil in open fields, prairies, open woods, thickets, roadsides, railroads, and river banks. Often used in naturalized areas and native or pollinator gardens.
Plant Characteristics:
Grows 2-6' tall.
Prefers full or part sun.
Prefers well-drained, dry to moist soils, including loam, clay, gravel, and sand. Does not tolerate fertilization and would rather be dry than overly wet.
Half-inch-wide flowers have 4 fan-like petals on the upper side and 8 prominent stamens and 1 pistil on the lower side, arranged horizontally to the petals. The stamens have reddish-brown anthers. Color fades from white to pink as the flowers age. Diamond-shaped fruits appear July-November.
Stalkless stem leaves are opposite, narrow, lance to elliptical shaped and 3-7" long. Margins are smooth or slightly toothed. Undersides have short hairs.
Green stems may be angular or round and red-tinged with spreading white hairs.
Wildlife Value:
Host plant for 5 species of Lepidoptera larvae, including specialists primrose flower, white-lined sphinx (both pictured here with their caterpillars) and clouded crimson moths. The seeds are a food source for birds and other wildlife.
Resources:
Ladybird Johnson Wildlife Center: https://www.wildflower.org/plants/result.php?id_plant=OEGA.
North Carolina Extension: https://plants.ces.ncsu.edu/plants/oenothera-gaura/.
Native Plants with Adam: https://adamsgardennativeplants.blogspot.com/2011/10/biennial-beeblossom.html.
Illinois Wildflowers: https://www.illinoiswildflowers.info/prairie/plantx/gaurax.htm.