Description: This native perennial plant is ½–2' tall, branching occasionally from the leaf axils. The stems are erect or have a tendency to sprawl, sometimes rooting at the leaf nodes. They are covered with long white spreading hairs. The opposite leaves are up to 3" long and 1½" across. They are pinnatifid and sharply lobed (cleft), but broadly lanceolate or ovate in overall form. The margins are coarsely serrated, while the base of each leaf is sessile or tapers to a winged petiole. The leaves are often pubescent and slightly ciliate, with a rough texture.
The major stems terminate in an
inflorescence consisting of a short flattened spike, densely crowded with
flowers. The flowers are individually about ½" across, and usually pink
or lavender – rarely do white or purple forms occur in the wild. The hairy
reddish calyx of each flower is partitioned into 5 triangular sepals. The
corolla tube is long and narrow, but abruptly flares outward into 5 petals that
are sometimes notched at their tips. There is a pleasant floral scent. The
blooming period occurs from late spring to early summer, lasting about 2
months. Some plants may bloom later and longer, but this is the exception to
the rule. The seeds are without tufts of hair, and may fall to the ground only
a short distance from the mother plant. The root system consists of a stout
taproot, which may send up multiple stems at the base of the
plant.
Cultivation: The preference
is full to partial sun, and mesic to dry conditions. The soil can contain rich
loam, sand, or gravel. Plants that are not native to Illinois may not be
reliably winter hardy in Zone 5. Therefore, it is important to obtain seed or
plants that are local to the area.
Range &
Habitat: Rose Vervain occurs in scattered counties of Illinois (see
Distribution
Map). This plant is absent from NW Illinois and some southern areas,
otherwise it is uncommon. Some local populations in
the wild are
undoubtedly plants that have escaped cultivation. It can be difficult to
distinguish native from introduced varieties, but the former are more likely to
be winter hardy and can persist for decades. Habitats include mesic to dry
black soil prairies, sand prairies, gravel prairies, slopes and openings in
rocky or sandy woodlands, limestone glades, bluffs, pastures and abandoned
fields, and borders of lakes. Pioneer cemeteries and rocky moraines are good
locations to discover this plant. Illinois is at the northern end of the
distribution for Rose Vervain, which occurs in many southern
states.
Faunal Associations: The
nectar of the flowers attract long-tongued bees, butterflies, and skippers. The
caterpillars of Crambodes talidiformis (Verbena Moth) feed on the
foliage. Mammalian herbivores are unlikely to consume this plant because of the
bitterness of the leaves. The seeds may be carried off by small rodents or
birds, and perhaps dispersed by them to a limited extent.
Photographic
Location: The photographs were taken at Loda Cemetery Prairie in
Iroquois County, Illinois.
Comments:
This is a beautiful plant with flowers that are similar to phlox. However, the
ragged appearance of the leaves sets it apart from the latter species.
Cultivars offer a greater range of flower colors and their leaves are often
dark green. The Rose Vervain in the photographs was located on the gentle north
slope of a pioneer cemetery, where a remnant of mesic black soil prairie
occurs.