Pelargoniums on parade

Pelargoniums are pretty perennials that are to be found everywhere - spilling from window boxes and hanging baskets, adding splashes of colour to hotels and restaurants and beautifying sporting venues, schools and other public places.

Pelargoniums are hardy, versatile and interesting garden plants, ideal for sunny borders, patio pots, window boxes or even the herb garden, where the scented-leafed varieties can be planted amongst your kitchen garden crops. Although many perlargoniums bloom from spring through to autumn, their most floriferous period is from spring through to early summer.

There are about 250 different species of pelargoniums and hundreds of newer cultivars. Most of these species are indigenous to South Africa, and are found mainly - although not exclusively - along the east and west coasts and the Cape peninsula.

Pelargoniums for the garden

Pelargoniums can be divided into four main groups:

Zonal pelargoniums

These showy plants are perhaps the best known of all the pelargonium types. Typically - although not always - zonal pelargoniums have a horseshoe marking on the foliage. Their blooms may be single, semi-double or double and the colour range is endless, often with bi-colours, outlining, splashing or veining. The modern cultivars are 20-50cm tall, while the older ones grow up to 1m, and they flower on and off all year. They will tolerate mild frost. 

Uses: In garden borders, in containers, and the low-growers as ground covers. 

Ivy-leafed pelargoniums

These are often known as trailing or basket pelargoniums, due to their scrambling growth habit, and these are the plants that are so popular in window boxes and hanging baskets. Each leaf is shaped just like an ivy leaf with five pointed angular lobes. The ivy-leafed pelargoniums flower on and off all year round, and will tolerate mild frost. 

Uses: Trained up a fence or trellis, in hanging baskets, trailing down a retaining wall or rockery, or as a ground cover. 

Regal pelargoniums

This group has large showy blooms in every colour with veining, flecking or blotching. They are all descendants of P. cucullatum, which grows on Table Mountain. Regals start flowering later than other groups, when the weather has warmed up, and flower for three months. Their height and spread varies from 0,5m to 1m, and they are frost-tender plants. Prune after flowering to prevent leggy growth habit. 

Uses: Plant in well-drained soil in borders and containers in frost-free gardens. In gardens with mild frost, grow in a warm frost-free part of the garden.

Scented pelargoniums

Most scented pelargoniums are grown for their aromatic foliage rather than the insignificant flowers. They have foliage in many different shades of green and in many different shapes. The most well known are: - Rose-scented (P. graveolens, P. radens and P. capitatum). - Peppermint-scented (P. tomentosum). - Balm-scented (P. vitifolium). - Coconut-scented (P. grossulariodes). - Lemon-scented (P. citronellum). - Apple-scented (P. odoratissimum). - Nutmeg-scented (P. x fragrans)

Uses: They are grown mainly for their scent and attractive foliage, which will enhance any floral arrangement.

Tips for success

  • Plant pelargoniums in well-drained soil in a sunny position.
  • They will tolerate wind.
  • Plant in a frost-free position. In cold gardens, choose a spot with a warm microclimate.
  • Single ivy-leafed pelargoniums cope best in hot positions.
  • Pelargonium hybrids do not like too much heat.
  • Avoid overwatering pelargoniums - they are dry climate plants.
  • Pelargoniums grown in containers prefer morning sun and afternoon shade, but if in a hot west-facing position they cope better once the foliage covers the surface soil area.
  • Apply a light dressing of potassium-rich fertiliser in spring to promote flowering.
  • Prune back after flowering to prevent legginess.

Geraniums vs pelargoniums

The plants we all know as geraniums are correctly called pelargoniums, having 'borrowed' their common name from a member of the same plant family, Geraniaceae. The true geranium is found in many parts of the world, while most pelargoniums have their origins in South Africa. You can distinguish between the two by examining their petals - geraniums have five similar petals, whereas the pelargonium's flower consists of two large and three slightly smaller petals.

New plants from old

    • Step 1. Choose a healthy shoot (stem and leaf section) about 4cm long.
    • Step 2. Make a clean, slanted cut just below a node (leaf joint). Remove the larger lower leaves flush with the stem.
    • Step 3. Remove the flower and any small leaf-like stipules (modified leaves) from the base but be careful not to damage the stem as this may promote disease. Remove any diseased or dying foliage, buds or blooms.
    • Step 4. Dip the tip of the stem in hormone rooting powder.
    • Step 5. Pot-up the cutting in the potting mixture. Place in a warm well-lit position and leave uncovered.

    Pelargoniums are very easy to propagate from cuttings. Cuttings are taken from a mature plant, which must essentially be a healthy plant. Late summer is best time to make these cuttings and your new plants will be ready to plant out in spring. Make sure the knife you use is scrupulously clean, so as not to promote disease in your new plant.

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