Northern Ontario Plant Database

Plant Description

Diervilla lonicera Mill.

En: northern bush honeysuckle, bush honeysuckle
Fr: dièreville chèvrefeuille, herbe bleue
Oj: wezauskwagmik, osawa'skanet

Caprifoliaceae (Honeysuckle Family)

Click on thumbnail to see larger image.

General: A low, mound-forming, deciduous shrub, usually about 0.5 m tall, seldom reaching 1 m tall in our area, and often forming extensive colonies through underground rhizomes. Northern bush honeysuckle is suitable for use in revegetation projects as well as home landscaping due to its attractive yellow to orange flowers and colourful autumn foliage.

Stems/twigs: Terminal buds are lacking on previous year's flowering branches; new growth originates from lateral buds. Lateral buds are opposite, lanceolate, scaly, with about 5 pairs of small overlapping (imbricate) bud scales, and curve inward slightly towards the twig. Young stems are green to reddish; woody stems are slender, smooth (glabrous), with grey or reddish-brown bark, and marked with 4 lines extending downward from the edges and lower margin of the opposite leaf scars; older woody stems have thin shreddy bark. Leaf scars are narrowly elliptic with 3 bundle trace scars.

Leaves: Opposite, simple, pinnately-veined. Petiolate are short, up to 1.2 cm long. Leaf blades are lanceolate to ovate, 5—13 cm long by 1.5—6 cm wide. The upper surface is dark green and smooth (glabrous), lower leaf surface is paler, glabrous to somewhat hairy. Leaf base are rounded to slightly cordate; the apex is sharply pointed (acuminate); margins are toothed (serrate) and somewhat hairy. Plants growing in open sunny locations often have bronze or reddish-tinged leaves; plants growing in heavy shade have larger broader green leaves.

Flowers: Bisexual, but self-incompatible, with the female organ (pistil) receptive before pollen is shed. Flowers are borne in terminal or axillary clusters (cymes) of usually 3 stalked flowers. The calyx tube is narrowed in the upper third and topped by 5 slender calyx lobes that persist in fruit. Flowers are pale yellow, but turn orange or reddish after pollination. The corolla is funnelform, 1.2—2 cm long, 5-lobed and bilabiate, with 2 upper lobes and 3 lower lobes, the middle of the 3 lower lobes is hairy and more deeply coloured than the adjacent corolla lobes. Five stamens are attached to the inside of the corolla base (epipetalous); the single pistil has an inferior ovary with a long-exserted style terminating in a large capitate stigma. Flowers bloom in June and July.

Fruit: A dry many-seeded capsule, oblong to narrowly ovoid, 1—1.5 cm long, narrowing at the top into a beak and crowned by the persistent star-like calyx, which has 5 slender spreading lobes. Capsules mature in late summer and dehisce along the carpel divisions (septicidal capsules), often remaining on the stems well into winter.

Habitat and Range: Dry forests, rocky shores and thickets, clearings and forest edges. Northern bush honeysuckle is native to northeastern North America. In Ontario, its range extends throughout the boreal forest, but is absent from barren and tundra habitats. It occurs throughout the Algoma District and extends as far north as Sandy Lake [53° N] (Soper & Heimburger 1982, Scoggan 1978).

Similar Species: Northern bush honeysuckle is in the same family as true honeysuckles (Lonicera spp.) and has similarly-shaped flowers. But true honeysuckles have flowers borne in pairs, with the 2 ovaries partially fused at the base, calyx lobes are greatly reduced, their fruits are fleshy berries, and their leaves have entire margins. In contrast, Diervilla has flowers usually borne in clusters of 3 flowers, each with separate ovaries, calyx lobes are long narrow and persistent on the fruit (a dry capsule), and their leaves have serrate leaf margins.