Wild petunia
Wild petunia (Ruellia spp.) is an easy-togrow,
lavender- to blue-owered native
that works well in most conditions. It is
endemic to the eastern United States,
where its range extends from New Jersey
southward and west to Texas. In Florida, it
is found in sandhills, atwoods and moist
to wet hammocks in about 52 counties.
There are ve species of Ruellia native
to Florida, but Ruellia caroliniensis is
the most common, both in the wild and
commercially. Other species include
Ciliate wild petunia (Ruellia ciliosa)
and Thickleaf wild petunia (Ruellia
succulenta), endemic to South Florida. A
non-native species of Ruellia is commonly
available for purchase but should not be
used as it is invasive. (See Caution.)
Description
Wild petunia is a long-lived perennial that
can attain a height of 12 to 18 inches.
Its 5-petaled blooms are tubular, grow
to about 1 to 2 inches, and appear in
clusters along multi-branched stems. It
resembles the common garden petunia,
although they are not related. Its simple
leaves are green with an ovate to elliptic
shape and are oppositely arranged
on stems. R. caroliniensis is easily
distinguished from other Ruellia species
by the long, pointed sepals and bracts
that surround the ower’s base.
Wild petunia’s showy owers last only a
day, but successional blooms keep the
plant looking fresh with continuous owers
spring through fall. In warmer parts of
the state, it may bloom year-round with
smaller owers. In colder climes, Wild
petunia may die back in winter and return
in spring.
Planting
Wild petunia does well in a mixed
wildower bed of plants and grasses. In
North Florida, it is not recommended for
a mass planting as it will be a patch of
stems during the winter.
Plant Wild petunia 12 to 15 inches apart,
or grow it in a hanging basket or large,
well-drained container. Wild petunia is
one of the few wildowers that will bloom
in partial to slightly denser shade.
Seeds
Seeds are generally not commercially
available. To grow this plant from seed,
collect mature capsules in a paper bag
in mid- to late summer. Seeds gradually
ripen on the plant over a period of weeks,
so visit plants several times to check the
capsules. They will turn from bright green
to brown when mature.
Stem cuttings are also an easy way to
propagate it. Take 3- to 4-inch cuttings
in the summer from exible stems. Plants
root easily in 3-4 weeks.
Plants
Plants are widely available from native
nurseries in various pot sizes, and can be
planted throughout the growing season.
Care
Wild petunia may need trimming halfway
through its growing season to promote
new growth and
blooms. Remove
3-4 internodes (4-6
inches) with scissors
or clippers. Annual
pruning may be
required to remove
old stems.
Wild petunia is a prolic self-seeder and
may form colonies over time. (Like other
members of the Acanthaceae family, its
mature seed capsules will explode open,
sending seeds far from the parent plant.)
Plants have a strong root system, making
them easy to transplant.
Site conditions
This plant adapts well to varied sun and
soil moisture conditions. It will thrive in a
moderate-to-dry sunny location but also
tolerates shade and even wet, mucky
soils. Establishing Wild petunia in shadier
locations will result in plants that appear
lanky with fewer blooms. Plants have
some salt tolerance.
Hardiness zones
WIld petunia is best suited for zones
8a–10b.
Several buttery species, including
the White peacock, Malachite and
Mangrove buckeye, gather nectar
from Wild petunia. It is a host for the
Common buckeye. The blue corollas
attract a variety of bees, including
bumble bees, leafcutter bees and
honey bees.
12–18 in
Nectar, host
Although the nursery
industry offers some
sterile non-native
CAUTION
Ruellia, the widely grown
Mexican petunia (Ruellia
simplex; synonyms R.
brittoniana and R. tweediana) should
be avoided as it may reproduce
via underground rhizomes. As a
Category I invasive exotic species, it
has spread into municipal and natural
areas, displacing native species and
changing community structures or
ecological functions.
Photo by Ron and Diane Bynum
Wild petunia
Photo by Kitty Loftin
Gulf fritillary on Wild petunia
Photo by Mary Ellen Gotto
Wild Petunia is best in a mixed planting.