A family of long-flowering, showy tender annuals and herbaceous perennials. Available in a range of differing colours and flower types. Ideal for a sunny border where they will attract beneficial insects and butterflies to the garden.
Family: Asteraceae (Daisy family)
Botanical Name: Zinnia (ZIN-ee-ah)
Common Names: Youth-and-old-age
Foliage: Deciduous, simple lance-shaped, green leaves.
Flowers: Bright daisy-like flowers in a range of colours (red, pink, orange, lavender, yellow and white). Most hybrids have semi-double or double flowers.
Flowering Period: July to September.
Soil: Moist but well-drained, fertile soil (chalk, clay, sand or loam). Acid, alkaline or neutral pH.
Conditions: Best in full sun. Grow in a west or south facing aspect, in a sheltered location.
Type: Half-hardy Annual.
Origin: Central and South America.
Hardiness: Tender in the UK. Protect from frost.
Best in a light, fertile, humus rich soil, in warm sunny beds or borders. Incorporate plenty of well-rotted garden compost or humus to the soil at planting time. Note: Zinnias are very fussy about conditions so it's not worth growing them if your soil is poor and the site is shady.
Ideal for borders, bedding or as cut flowers. Dwarf and intermediate forms are good for the small garden as well as in larger bedding schemes.
Tall varieties are useful as cut flowers, which last well in water.
Water regularly during dry weather and water container grown plants daily.
To improve flowering, apply an all-purpose flowering plant food (slightly higher in phosphorus and potassium) every few weeks, or use a slow release form.
Pinch out growing tips on young plants to encourage bushyness.
Deadhead regularly to extend the flowering period.
Can be affected by grey moulds, powdery mildews and a leaf spot, especially in cool, damp summers.
Sow seed in April in greenhouse or propagator, at 16-18°C (60-64°F). When large enough to handle, prick out into individual pots or modules so they can be transplanted with the minimum of root disturbance. Harden off before planting out in late May or early June.
Alternatively, sow seed thinly in a prepared seed bed in May, where they are to flower. Gradually thinning to 12in (30cm) apart.
Zinnia angustifolia light green, slightly hairy leaves and stems topped with bright daisy-like flowers, in a range of colours. Flowers July to August. Height to 24in (60cm), spread 12in (30cm). Varieties include:
Zinnia elegans the parent of a number of modern varieties. It has pale green foliage and bright purple flowers. Flowers July to September. A wide range of cultivars are available, including dahlia-flowered, scabious-flowered and cactus-flowered strains, in many colours. Varieties include:
'Whirlygig Mixed' brightly coloured, semi cactus-like blooms, each with contrasting petal tips. For sale at Thompson & Morgan.
Zinnia marylandica (hybrid between Z. angustifolia and Z. elegans) a free-flowering disease-resistant strain with a good garden worthy habit. Height 12-24in (30-60cm). Cultivars include:
Zinnia haageana noted for its solitary long-stemmed flowers that come in a variety of bright colours. Cultivars include:
Zinnia Oklahoma Series (Hybrid) long flowering and weather tolerant. For sale at Crocus.
Zinnia Profusion Series (Hybrid) bushy annuals with single daisy-like flowers in shades of red, orange and deep pink. Short and compact in size, with profuse flowering and good disease resistance. Height to 1ft (30cm). Cultivars include: