Family: Asteraceae

With their range of very brightly coloured flow­ers, zinnias make an attractive display when mass planted, while the dwarf types are decorative in borders. There are around 20 species in this genus of annuals and perennials, with a wide distribution through drier parts of the Americas and Mexico. Zinnias, which are frost-tender, are widely grown as summer bed-ding plants.

Species

Z. elegans is an upright-growing annual that may reach 80 cm (32 in) or more high. It is sometimes known as 'youth and old age' because of its habit of producing new flow­ers and growth that mask the old, faded blooms. It has stiff, stem-clasping leaves, and the large flowers have rows of overlapping petals (ray florets). The species has purple flow­ers and is rarely grown, its many cultivars being preferred. There is a vast colour range, including yellow, red, pink, cream, white and purple. There is even a green cultivar called 'Envy'. Most cultivars have double flowers, but some are single or semi-double. There are tall-grow­ing kinds up to 80 cm (32 in) in height, medium growers, to 60 cm (24 in), and small growers, about 15-40 cm (6-16 in).

The annual Z. haageana, Mexican zinnia, grows to 60 cm (24 in), with brilliant orange flower heads. There are several cultivars, including dwarfs in mixed colours as well as the original orange, and these are ideal for summer bedding. The culti­var 'Persian Carpet', 40 cm (16 in) high, is grown worldwide.

Cultivation

In frost-prone climates, raise bed-ding plants from seed in early spring, under glass, germinated at 18°C (64°F) and plant out when frosts are over. If there is no risk of frost, seeds can be sown where they are to grow, in late spring. Zinnias grow best in a fairly rich soil, well drained yet moisture-retentive with plenty of humus. Full sun ensures optimum flowering. Remove dead flowers to encourage a long flowering period.

Climate

Zone 10, but grown as summer annuals in all climatic zones.