How to plant and grow pelargoniums

A really healthy, bushy pelargonium (also known as a geranium) is a wonderful thing to see, filling a handsome pot during the summer. The varieties grown for their flowers can be arranged top to toe in tiers, from June until November. Then there are the scented-leaf ones, pert-looking, healthy and abundant. Whenever you brush past them, they fill the air with scent; with the quick-growers, you can pick a sprig, guilt-free, to crush in your fingers whenever you pass.

They can be grown as bedding outside during the summer months, or in containers, but they are not hardy so must be brought inside before the onset of frost. They also make ideal houseplants and are fantastic decorating a conservatory.

Planting

In the garden

Plant in fertile moist soil after all risk of frost has passed. Most cultivars prefer full sun, but regal pelargoniums, e.g. 'Lord Bute', prefer part shade.

In containers

Grow in loam-less potting compost or in John Innes No 2 in full light, but with shade from hot sun, and good ventilation. Grow them in 4in pots of multipurpose potting compost. Once the pelargoniums have filled those, pot on into 2-litre pots before planting them with slow-release fertiliser (such as Osmocote) into their final pot in the middle of spring.

Water your pelargoniums sparingly every two to three days during their active growing season. Feed your pelargoniums with a homemade feed of comfrey juice, or organic liquid plant food – both rich in potash – every fortnight.

Aftercare and Maintenance

Dead-heading regularly helps prolong flowering and they'll need this more often in the rain. Please be aware that contact with the foliage may occasionally aggravate skin allergies.

Lift the plants with care and pot them up inside before the frost, cutting the top growth back by one-third as you do so. Pot on in late winter as growth resumes.

Take care to water sparingly during the winter. If kept at 7-10C (45-50F), plants may flower right through the winter. Otherwise cut back your plants, with care, by two-thirds and keep them almost dry until they begin to shoot in the spring, when watering can start again. You can take cuttings at that moment, too.

Propogating pelargoniums

Propagating pelargoniums is easy, with guaranteed results.  If you propagate them rather than growing on last years plants you'll have more floriferous and stronger plants.  

  • Start propagating pelargoniums in September, while plants are in a very active stage of growth. They will root very quickly.
  • Make a 1½ in - 3in cutting. You are most likely to succeed if you keep cuttings small.
  • Use a very sharp knife – a razor blade rather than a kitchen knife.
  • Use a mix of two-thirds peat to one-third grit.
  • Do not cover your pelargoniums like you would when propagating other tender perennials.
  • They should root within two to three weeks. You'll know they have done so by new growth at their tips. Turn over the pot and check for new white roots.
  • Take them out of the propagator and pot on if before October.
  • If it's already October, don't pot on but feed and keep them cold and dry through the winter, to pot on in spring. They'll grow fantastically and you'll have lots of plants to put out in the garden.

Cut Flowers

These will look good for up to 3 weeks in the vase.

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