Pelargonium
A large family of tender, evergreen, flowering perennials. Popularly grown in the UK as summer bedding or as pot and container plants.
Family: Geraniaceae
Botanical Name: Pelargonium
Common Names: Tender Geraniums
Foliage: Evergreen, palmately lobed or pinnately divided aromatic leaves.
Flowers: Flamboyant clusters of five petalled flowers. Available in shades of Red, pink, orange and white. In single and double forms.
Flowering Period: June to October.
Soil: Well-drained sand or loam. Acid, alkaline or neutral pH. Avoid waterlogged conditions.
Conditions: Best in full sun. Grow in an east, west or south facing aspect, in a sheltered position.
Habit: Bushy.
Type: Tender Perennial.
Origin: South Africa.
Hardiness: Tender in the UK - protect from frost.
Planting and Growing Pelargoniums
Geraniums thrive in any good well drained garden soil or compost. Plant indoor and container specimens in medium sized pots of John Innes potting compost No. 2 or No. 3. Harden off and plant outside in full sun from late spring, once all danger of frost has passed in your area.
Some forms have decorative or scented leaves. Variegated varieties can be highly attractive, although less floriferous. Both variegated and scented forms make excellent conservatory or houseplants.
The common varieties are useful in summer bedding schemes or in containers and hanging baskets.
Taking Care of Pelargoniums
Water pot grown plants freely during the growing period and more sparingly in winter. To improve flowering give plants an occasional high-potash feed every few weeks, or use a slow release form. Do not over fertilise.
Nip out the top shoots of leggy plants to make them more bushy. If large enough these shoots can be used to provide more cuttings.
Pruning
Deadhead regularly to extend the flowering period.
Choice varieties can be lifted in the autumn before the first frosts and potted up as houseplants. These can then be used as a source for cuttings in early spring. Once flowering has finished the stems can be back to around 3 to 4in above soil level or back to a leaf node.
Pests and Diseases
Susceptible to attack by a wide range of pests and diseases. Although, strong healthy plants will easily shrug off most problems.
Propagating Pelargoniums
Easily increased by softwood cuttings from spring to autumn, or from seed in the spring. Cuttings will readily root in a jar of plain water on the windowsill, although they root quicker in a free draining sandy compost under a propagator. Pot up into 3in (7cm) pots as soon as they have rooted and gradually harden-off before transferring outside.
Popular Varieties of Pelargonium
There can be some confusion between the hardy species of geranium (crane's-bill) and the more tender pelargoniums. Although both are commonly called geraniums, pelargoniums are easily distinguished due to their firm fleshy stalks and larger more flamboyant flower clusters. Numerous hybrids are available.
Pelargonium x domesticum (regal pelargoniums) are bushy plants with sturdy stems and mid-green, deeply serrated leaves. Round heads of brightly coloured, often double, flowers are carried above the foliage on slender stalks in June-August. Height from 1 to 2ft (30-60cm), spread 8 to 24in (20-60cm). The flowers often have darker central markings and are available in good range of colours, including white, pink, salmon, rose, violet, orange and scarlet.
Pelargonium x hortorum (zonal geraniums) have rounded, soft,
palmate leaves with a dark band or zone. Mainly pink, white or red flowers. Some cultivars
have attractive variegated or coloured leaves. Height 6-36in (15-90cm), spread 6-24in (15-60cm).
These are the most common geraniums sold in garden centers and shops in the spring. Providing reliable bedding plants that will flower right up until the first frosts.
Pelargonium peltatum (ivy-leaved geranium) produces trailing stems that carry fleshy, midgreen, ivy-shaped leaves. Pink or lilac flowers in summer. Height 6in (15cm), spread up to 4ft (1.2m). Trailing forms are very popular for hanging baskets and tubs. Variegated leaf forms are available.