Verbena are well known as popular annual summer bedding plants, but a number of species and varieties are reasonably hardy. Verbena rigida and Verbena bonariensis are two of the toughest species, however one of the choicest species available is Verbena hastata, which produces masses of very small flowers on architectural flower heads.
Verbena hastata is a different plant from most commonly seen Verbena, Proving to be hardy through most winters in well-drained, sunny spots, its sheer volume of flowers make it a real winner. It is understandably increasing in popularity as it becomes more readily available.
Verbena hastata 'Blue Spires' is the blue form of this lovely perennial, with multi-branching candelabra-like flower heads, the flowers slowly expand as they ascend the stems like burning sparklers. The flowers appear in mid-late summer and will last into late autumn, especially if they are dead-headed when a second flush will appear.
Easily grown in average, medium to wet soils in full sun the plants grow to a height of around 90 to 120cm (36 to 48in) tall. This hardy plant does not need staking, and provides lots of mid to late summer colour in the garden. The plants look good when combined with ornamental grasses and other floaty plants in a mixed border or as part of a prairie planting scheme and make an excellent good cut flower.
Sowing: Sow seed at 18 to 21°C (64 to 70°F) in autumn or early spring.
Sow very finely onto the surface of pots containing moist seed compost. 'Just cover' with a sprinkling of sieved soil (1/16th in) and cover the container with dark paper or similar as the seeds need the dark to germinate. Place the container in a dark place. Maintain an optimum temperature of 15 to 18°C (60 to 65°F)
Keep moist, watering from the base of the container but do not saturate the compost. Germination is usually around 14 to 28 days, but may take up to 90 days to finish germinating (especially if seeds haven’t experienced cold stratification).
Remove the cover once they begin to germinate to allow air to circulate (otherwise they may suffer from damping off) and reduce the temperature to around 15°C (60°F), keep in light but not strong sunlight, a warm kitchen windowsill is often sufficient.
Thin (prick out) seeds as they become large enough to handle, leaving the seed trays in tact for other seedlings that may germinate later. Use 7cm (3in) pots containing well drained compost mix. You can add 10% horticultural sand (that doesn’t contain salt) to a regular compost to achieve this.
Harden off young plants gradually for 10 to 15 days before planting out, Pinch back when first planting to encourage branching. Plant 45cm (18in) apart in a sunny position in ordinary garden soil. (Verbena is susceptible to the fungus mildew if planted in a wet, shady locale.) In poor soil it is worth incorporating some organic matter before planting.
Water deeply to encourage roots to grow deeply, resulting in a healthier, more drought tolerant plant. Avoid overhead watering if possible. Remove the faded flowers for a better following flowering.
Because it is borderline hardy, plants may be damaged by severe winter frosts. In winter mulch around the base of the plant with a deep, dry mulch to help protect the plant.
It is a short-lived perennial that self-seeds; the resulting seedlings are stronger and more drought-tolerant than those that are transplanted. Any plants lost to frost are normally replaced by their offspring.
They prefer dry, light and airy cultivation. Give the plants space and transplant any self sown seedlings that are growing near to each other. Verbenas do not require a particularly rich soil or fertiliser but will benefit from a light feed in spring.
Wildlife, Bee and Butterfly gardens. First year flowering, Gravel, City, Containers, Low-maintenance. Beds and borders, Cottage/Informal, Garden edging
Verbenas are beneficial for attracting wildlife, particularly butterflies.
It attracts: Brown Argus, Comma, Essex Skipper, Green-veined White, Large White, Meadow Brown, Painted Lady, Peacock, Red Admiral, Small Copper, Small Tortoiseshell, Small White and Hummingbird Hawk-moths.
The genus contains well over 250 species plus many garden hybrids. All but two are found in Latin America.
The genus name comes from the Latin Verbena, a classical name for certain sacred branches, probably of Verbena officinalis of Europe.
The species name hastata means 'spear-shaped', in reference to the basal lobes facing outward.
Verbena is member of a genus of perennial herbs which are sometimes known by the ancient name Vervain which is thought to be derived from the Celtic words fer meaning to remove and faen meaning stone, referring to its use in treating bladder stones.
- Additional Information
Packet Size 75mg Average Seed Count 250 Seeds Family Verbenaceae Genus Verbena Species hastata Common Name Blue vervain Other Common Names Hardy garden verbena Hardiness Hardy Perennial Hardy Hardy to minus 10°C (5°F) Flowers Blue Natural Flower Time June until October Height 90 to 120cm (36 to 48in) Spread 30cm (12in) Time to Sow Sow seed at 18-21°C (64-70°F) in autumn or early spring.