Height 15-60cm (6-24in)
Planting distance 20-30cm (8-12in)
Flowers late spring to mid autumn
Ordinary well-drained garden
Tender perennials, grown as half- hardy annuals
Formal beds, hanging baskets, window-boxes and pots on balconies all abound with brightly coloured pelargoniums in summer. These tender perennials, grown outdoors as half-hardy bedding plants, come in an enormous range of forms. The, which can be white, red, pink, rose-pink, salmon and mauve, are borne on either upright or pendulous plants, with variously shaped and coloured leaves.
Pelargoniums are divided into several groups, according to their hybrid provenance, flower type or general growth habit.
REGAL PELARGONIUMS, also known as Pelargonium x domesticum, are a hybrid race of erect, shrubby plants up to 60cm (2ft) tall, with light green lobed leaves that are lightly toothed.
The exotic flowers are borne in dense clusters, often veined or marked with contrasting colours and often with frilled petals. Suitable for pot cultivation, outdoors and under glass. ‘Applause’ has pink flowers with frilled petals.
‘Aztec’ has pink flowers with dark maroon veining and a white base.
‘Grand Slam’ has crimson-red flowers.
‘Velvet Duet’ has purple-pink flowers fading to white.
ZONAL PELARGONIUMS are the most commonly grown varieties, sometimes listed as Pelargonium x hortorum. Distinguished by their rounded, pale to mid green leaves, usually though not always with a conspicuous brown or maroon zone, the upright plants reach 30-60cm (1-2ft) in height. They are suitable for bedding schemes and containers and are available in numerous seed selections, mainly F1 hybrids:
‘Eyes Right’ has huge flower clusters in shades of pink and rose-red with scarlet eyes.
‘Hollywood Star’ bears tightly packed flower heads, rosy-pink and white-centred.
‘L’Amour’ is a seed mixture producing compact plants, branching from the base and bearing clusters of semi or fully double flowers in shades of pink, red and white.
‘Masquerade’ is a bicoloured mixture bearing scarlet, pink, cerise or salmon flowers, all with white eyes.
‘Orange Appeal’ has large, pure orange flower heads.
‘Orbit Series’ is available as a mixture or in single colours of apple-blossom pink, deep pink, scarlet, violet or white.
‘Ringo Scarlet’ has glossy, rich scarlet flowers above dark green, zoned foliage.
‘Ringo White’ has pure white flowers and light green leaves.
‘Sensation Mixed’, so-called floribunda geraniums, come as mixed seeds or in single colours of rose, scarlet, cherry, blush-pink and coral.
‘Startel’ has dense flower heads in white, shades of pink and red, and heavily zoned leaves.
Fancy-leaved pelargoniums have leaves so heavily marked that they outshine the flowers:
‘A Happy Thought’ has green leaves with yellow markings, and red flowers.
‘Mrs Henry Cox’ has yellow, green, red and copper leaves, with salmon-pink flowers.
Miniature zonal pelargoniums, suitable for window boxes and edging include:
‘Michelle’ has delicate salmon-pink flowers and zoned leaves.
‘Playboy Speckles’, 23cm (9in) high, compact and bushy, with bicoloured pink and white blooms.
‘Red Black Vesuvius’ is 15cm (6in) tall, with cerise-pink flowers and heavily zoned, almost black leaves.
‘Video Mixed’, to 25cm (10in) high, in a range of clear colours and with deep green, zoned leaves.
Cascading zonal pelargoniums do not trail but branch naturally from the base to cascade over hanging baskets, window-boxes and tubs:
‘Breakaway Red’ and ‘Breakaway Salmon’ are both 25cm (10in) tall, with deep red or salmon flowers and lightly zoned leaves.
‘Continental Cascade’ is a mixture of lilac-pink, rose-pink and orange-red, single flowers on short stems.
‘Palais’ bears large trusses of semi-double, coral-pink flowers.
‘Red Fountain’, single flowers of vermilion-red above strongly zoned leaves.
IVY-LEAVED PELARGONIUMS are trailing plants with stems up to 90cm (3ft) long and mid green fleshy leaves like those of ivy. They are ideal for hanging baskets and deep window-boxes. Varieties and hybrids bred from the species Pelargonium peltatiun include:
‘Butterfly’, compact, with double lilac flowers.
‘Cezanne’ has large shiny, vel-vety red flowers and rich green leaves.
‘Cornel’ has pink flowers with a hint of lavender in them.
‘Ingress’ bears compact clusters of clear rose-pink flowers.
‘Lulu’ trails to 45cm (1-1/2ft), and has deep violet flowers.
‘Mexican Beauty’ has single crimson flowers.
‘Salmon Queen’ has deep pink, semi or fully double flowers.
‘Snow Queen’ has double white flowers tinged with lilac.
‘Summer Showers’ has a mixture of pink, red, mauve and white flowers.
SCENTED PELARGONIUMS are grown for the strong scent of their leaves; they bear typical five-petalled flowers but these are small and insignificant. Suitable for pot and tub cultivation. ‘Chocolate Peppermint’ has peppermint scented leaves and blush-pink flowers. ‘Citronella’ has white flowers and leaves with a strong lemon scent. ‘Grey Lady Plymouth’ has foliage smelling of eucalyptus, and blush-pink flowers.
Pelargoniums are usually grown from cuttings though many zonal and ivy-leaved varieties are easily grown from seed. For cuttings, buy stock plants from a nursery or gar-den centre in late spring.
Take 7.5cm (3in) long tip cut-tings in mid to late summer and insert them in 6cm (2-1/2in) pots of potting compost, placed on an open greenhouse bench. When the cut-tings have rooted, pot them on as necessary.
Alternatively, overwinter mature plants in a frost-free greenhouse and take tip cuttings from these in early spring.
When young plants are about 15cm (6in) high, pinch out the growing tips to encourage bushy sidegrowth.
Sow seeds of zonal pelargoniums in late winter in pots or pans of seed compost at a temperature of 16-18°C (61-64°F). Prick out the seedlings into boxes and pot on as necessary.
Plant out pelargoniums between late spring and early summer, when all danger of frost has passed. Set them in ordinary well-drained soil in full sun.
In mid autumn, transfer the plants to pots of potting compost and keep them at a temperature of 10°C (50°F).
Pests and diseases
Whitefly sometimes gather on leaves.