Purpletop Vervain (Verbena bonariensis)

How much light does a Purpletop Vervain need?

Plant verbena bonariensis in full sun outdoors for the best results, since it prefers six or more hours of direct sunlight a day. It also tolerates part shade, managing on as little as two hours of direct sun a day. Full sun is the preferred choice for this species, which does best in a spot that gets sun throughout the day.

• Light: Full sun and part shade (full sun preferred)^1,2
• Direct sun: 2 h/day¹

How often to water a Purpletop Vervain

Water this plant anywhere from dry to medium conditions, since it tolerates that full range. It also tolerates a variety of soil types and average to dry conditions, along with full sun. The soil it typically grows in drains well and can be moist or occasionally dry.

• Water: Dry to medium¹

Best soil for a Purpletop Vervain

This plant needs soil with good drainage, since well-drained ground is required wherever you plant it outdoors. Beyond good drainage, the soil can stay moist at times or turn occasionally dry without trouble for this plant. It also tolerates a wide variety of soil types, plus conditions that run from average to dry. Choose a planting spot with soil that drains freely and gets full sun.

• Soil drainage: Well drained, moist and occasionally dry^1,2

Hardiness and temperature

Verbena bonariensis is a herbaceous perennial that grows outdoors in USDA hardiness zones 7a through 11b. That range covers zones 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, 11a, and 11b. In the United States, it is recorded as introduced in the lower 48 states, Hawaii, and Puerto Rico.

• Hardiness: Zones 7a–11b¹

Pruning a Purpletop Vervain

Prune verbena bonariensis by removing dead growth and lightly shaping the plant as needed. Also deadhead spent flowers. You can also trim the whole plant back by about one fourth of its height and spread. This plant has a rapid growth rate.

• Pruning: Remove dead growth only, Light shaping and Deadheading²

How to plant a Purpletop Vervain

Outdoors, this plant grows as a perennial in USDA hardiness zones 7a through 11b. Space plants roughly 2-3 ft (0.61-0.91 m) apart, in order to match its mature spread. This plant also reaches a mature height of 4-5 ft (1.22-1.52 m) with an erect growth habit.

• Hardiness: Zones 7a–11b¹

Winter care

This plant survives cold winters outdoors as a perennial within USDA hardiness zones 7a through 11b. No cited source gives a specific minimum winter temperature in degrees for this plant. The USDA hardiness zone range of 7a to 11b is the most specific guidance available.

• Hardiness: Zones 7a–11b¹

How to propagate a Purpletop Vervain

You can propagate verbena bonariensis from seed, or you can take root cuttings to start new plants. Both methods are listed as ways to grow new plants of this species. This species is a herbaceous perennial with an erect growth habit. This plant blooms in shades of purple from August to October.

• Propagation: Seed and root cuttings¹

Common problems

Common pests recorded for this plant include aphids, whiteflies, thrips, spider mites, and leafminers. Other pests include caterpillars, gall midges, true bugs, cottony cushion scale, broad mite, and cyclamen mite. Slugs and snails are also recorded as pests of this plant. Diseases recorded for this plant include powdery mildew, botrytis blight, root rot, and leaf spot.

• Common pests: aphids, whiteflies, thrips, spider mites, leafminers, caterpillars, gall midges, true bugs, cottony cushion scale, broad mite, cyclamen mite, slugs and snails^3,2
• Common diseases: powdery mildew, botrytis blight, root rot and leaf spot^3,2,1

Questions and answers

Does verbena bonariensis need full sun?

Full sun is best for this plant, though it also tolerates part shade. It can manage on as little as two hours of direct sun a day.

What hardiness zones suit verbena bonariensis?

It grows outdoors as a perennial in USDA hardiness zones 7a through 11b. No cited source gives a minimum winter temperature for it beyond that zone range.

How do you propagate verbena bonariensis?

You can grow new plants from seed or from root cuttings, since both are listed as propagation methods for this species. This species also grows at a rapid rate.