Verbena Seeds

Garden verbena (Verbena × hybrida) is one of the most cheerful bedding flowers you can raise from seed. It grows as a low, spreading annual, roughly 15-45 cm tall and 15-60 cm wide, smothering itself in dense clusters of small, brightly coloured blooms. Its tidy, mounding habit makes it a favourite for edging borders, filling beds and trailing softly over the rim of pots and window boxes, where it flowers tirelessly from late spring into autumn.

Planting

In Egypt, treat verbena as a cool-season annual: sow seed indoors or in trays in early autumn (September-October) and transplant out in October-November so plants bloom through the mild, frost-free winter and spring. Sow on the surface of damp compost and cover only with a thin layer of vermiculite, since light aids germination. Keep on a warm windowsill and germinate at about 21-27°C; seedlings usually emerge in 2-3 weeks. Keep the medium on the dry side until emergence to avoid damping off. Space plants about 50 cm apart in full sun (at least 6-8 hours daily) in well-drained soil.

Fertilizing

Apply a light feed of a complete fertilizer such as 16-4-8 in mid- to late spring, and again after you trim the plants back. Plants in poor soil may need feeding a little more often, but avoid over-fertilizing. For container verbena, a potassium-rich liquid feed such as tomato fertiliser encourages flowering, starting about a month after potting.

Care

Verbena demands well-drained soil and will not tolerate ground that stays wet, which causes root and crown rot. During bloom, give one thorough watering per week if rainfall has not supplied about 25 mm, watering at the base rather than overhead to limit disease. Deadhead for continuous flowers; if blooming slows in the heat, cut the plant back by about a quarter, then water and feed lightly to renew it within 2-3 weeks. Watch for spider mites, aphids, whitefly and powdery mildew, all reduced by full sun and good air flow.