Glandularia canadensis
Common Name: verbena
Type: Herbaceous perennial
Family: Verbenaceae
Native Range: United States
Zone: 5 to 9
Height: 0.50 to 1.50 feet
Spread: 1.00 to 2.00 feet
Bloom Time: May to August
Bloom Description: Rose-pink to rose-purple
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Annual, Ground Cover, Naturalize
Flower: Showy
Tolerate: Drought, Dry Soil, Shallow-Rocky Soil

Culture

Easily grown in average, dry to medium, well-drained soils in full sun. Avoid wet, poorly drained soils. Self-seeds in optimum growing conditions. May be grown as an annual throughout the normal range for the species, and in particular in the northern parts of USDA Zone 5 where it is not reliably winter hardy and appreciates some winter protection.

Noteworthy Characteristics

Glandularia canadensis is commonly called rose verbena, clump verbena or rose vervain. It is a Missouri native perennial that typically occurs in prairies, fields, pastures, rocky glades, roadsides and waste areas in the central and southern parts of the State (Steyermark). It is a clumping, sprawling plant that grows to 6-18” tall, and can spread rather quickly by pubescent, decumbent stems, rooting at the nodes where they touch the ground, to form an attractive ground cover. Flat-topped clusters of 5-petaled, rose-pink to rose-purple flowers appear atop ascending stems in a long, late spring to late summer bloom. Deeply lobed dark green leaves (to 4" long) have triangular bases.

For many years, Glandularia canadensis was known as Verbena canadensis. Many prestigious authorities (e.g., The Royal Horticultural Society) still list the plant as Verbena canadensis. The revised edition of Steyermark's Flora of Missouri (Yatskievych and Turner) now lists the plant as Glandularia canadensis. Glandularia is considered by many authorities to be a genus that is separate and distinct from Verbena based upon a number of factors including plant morphology, chromosome number, style length, reproductive modes and ploidal levels (see Umber, The Genus Glandularia (Verbenaceae) in North America, 1979).

Genus name from Latin means acorn in probably reference to the shape of the seedpod.

Specific epithet means of Canada.

Problems

No serious insect or disease problems. Some susceptibility to powdery mildew. Botrytis blight and root rot may occur in wet soils. Snails and slugs may attack the foliage. Watch for spider mites, particularly in dry conditions.

Garden Uses

Mass in rock gardens or border fronts. Spreads to form an attractive ground cover with a long and floriferous summer bloom. Edging. Containers. Hanging baskets.