Buddleja davidii Franch.

Common Butterfly Bush

© SRTurner

Family - Scrophulariaceae

Habit - Shrub.

Stem - Arching and spreading, to 4 m, pubescent with minute stellate hairs, also with small, light yellow glands.

	Stem and node.
© SRTurner

Leaves - Opposite, sessile or short petiolate. Blades elliptic or lanceolate, sharply pointed, upper surfaces sparsely hairy, lower surfaces tomentose and moderately glandular, appearing whitish. Margins finely toothed. Stipules herbaceous, appearing as small flaps of tissue between leaf bases.

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

	Leaf surface comparison.
© SRTurner

Inflorescence - Terminal on branches, dense panicles to 20 cm long.

	Inflorescence.
© SRTurner

	Inflorescence.
© SRTurner

Flowers - Calyx 2.5-4.0 mm long, actinomorphic, hairy, glandular, shallowly 4-lobed, lobes triangular. Corollas 9-12 mm long, actinomorphic, trumpet-shaped, internally hairy, lobes with irregular margins, bluish purple with an orange throat. Stamens 4, inserted. Ovary 2-locular. Style inserted, with single club-shaped stigma.

	Calyces and corolla tubes.
© SRTurner

	Corollas
© SRTurner

Fruits - 6-8 mm long, narrowly ellipsoid to cylindric-ovoid. Seeds 2-4 mm long, ellipsoid, slightly flattened, tapered to a slender wing at each end, the surface smooth, brown.

	Immature fruits.
© SRTurner

Flowering - July - October.

Habitat - Roadsides, homesteads.

Origin - Native to Asia.

Lookalikes - None.

Other info. - This species is often cultivated as an attractant for butterflies and other insects, and for its attractive and unusual appearance. In the wild it is usually found only at former homesites, persisting from deliberate plantings, and rarely escaping cultivation in Missouri. In fact, the first escape in Missouri was first noted by Mühlenbach in 1979. It is relatively uncommon throughout most of the U.S., except for the Pacific Northwest, where it is considered a pest. The flowers are sources of nectar and attract butterflies.

Some botanists have place the species (and others in the genus) into the family Buddlejaceae. Otherwise, Buddleja is one of the few Missouri genera remaining in the Scrophulariaceae following recent reevaluation of that family.

Photographs taken near Washington, Franklin County, MO, 8-27-2017 (SRTurner).