Family: Solanaceae

Originating from warm areas of the Americas, this genus of about 40 species of bright annuals and perennials is closely related to the tobaccos and a member of the same family as the potato. Among the most popular flowers in the world, they add colour to the porch or verandah when planted in hanging baskets or pots, and also make delightful bedding plants.

Species

P. hybrida, or hybrid petunia, is thought to be derived from P. axillaris and P. integrifolia. The flowers may be single or double, fluted, saucer- or trumpet-shaped, and come in a great range of colours, including many bi-colours and those with a contrasting edge. There are a great many cultivars of petunias and these are inclined to vary from one country to another. Consult mail-order seed catalogues to find out what is available. Most catalogues list a comprehensive range of cultivars. The hybrid petunias are split into two groups.

The Multiflora petunias are generally bushy plants, although some have a trailing habit. They have comparatively small flowers but the plants are very free flowering and make a tremendous show of colour. The Multifloras are favourites for summer bedding, as well as patio containers, and most tolerate wet weather quite well. The Grandiflora petunias have much larger flowers and they are not as tolerant of inclement weather. They are good for containers like hanging baskets and window boxes, particularly when sheltered from the elements.

Cultivation

Plants for bedding out in summer are raised from seed in a heated greenhouse. Sow seed in mid-spring and germinate at 18°C (64°F). Transplant seedlings to seed trays and grow on under glass. Plant out when frosts are over, in late spring or early summer, after hardening in a garden frame. Plants need well-drained soil, full sun and wind protection. Remove dead heads to encourage more flowering.

Climate

Zones 9 to 10; grow as summer annuals in all climatic zones.