Freesia

Their bright colours and heavy perfume make freesia a popular cut flower. Freesias are native to South Africa where they are winter growing plants and are frost tender. The modern hybrid freesias, Freesia × kewensis, are derived from crosses between Freesia refracta and Freesia armstrongii. Prepared corms planted outside in April will flower in late summer or they can be grown in a cool greenhouse for spring flowering.

<EM>Freesia corymbosa</EM> from RHS Lindley Library collection

Quick facts

Common name Freesia
Botanical name Freesia
Group Deciduous cormous perennial
Flowering time July August
Planting time April for prepared corms
Height and spread 40cm (16in)
Aspect Sunny/well-lit
Hardiness Tender minimum of 5°C (41°F)
Difficulty Moderate

Cultivation notes

Outdoor planting

Prepared corms are heat treated to mimic the hot dry South African. These are available in spring for flowering in July and August but will only flower at this time for one season. Plant 5cm (2in) deep in April, in moderately fertile, well-drained soil. Site in a sunny, sheltered spot with twiggy sticks or wire for support.

Unprepared corms: Available late summer for planting outdoors in August or September. Only suitable for very mild districts with very little frost and these corms can remain in-situ to flower in spring the following year.

Indoor or greenhouse planting

Indoors, corms will flower from January to April if planted between August and December. An October planting should under ideal conditions, flower in March for a period of four to five weeks.

  • Pot using two-thirds John Innes No2 and one-third grit
  • Space corms 5-8cm (2-3in) apart with the tips of the corms just above the soil level
  • Water after planting and place in a cool, frost-free area such as a cold frame, at 5°C (41°F) for three to four weeks
  • Transfer pots to a cool greenhouse or similar situation and maintain at 10-15°C (50-60°F) throughout winter
  • Provide as much light and ventilation as possible and don’t allow the plants to dry out
  • Support new growth with twigs or wire mesh as stems develop
  • Apply a high potassium  feed fortnightly from when the first buds are seen
  • After flowering cut off faded blooms and continue to water and feed until the foliage begins to brown, then cease watering. A period of at least eight weeks of growth is required  to encourage offsets. If growing on for a second year the foliage needs to dry off by early July
  • After lifting, a dry, warm period simulating the dry South African summer is required to ripen the corms. Maintain corms at 30°C (85°F) for three months either on a sunny windowsill or airing cupboard. Without this the corms may remain dormant for some time after replanting before beginning sporadic, slow growth

Propagation

Freesias are usually increased by corm offsets.

They can also be grown from seed in about seven to eight months but may not flower for a few seasons;

  • Cover the seed with warm water and soak for 24 hours  to soften the hard seed coat before sowing
  • Germinate in the dark with bottom heat at 13-18°C (55-64°F) pots can be cover with aluminium foil
  • Seedlings emerge after one to several months
  • Pot seedlings individually, don’t allow seedling corms to dry out
  • Grow on at minimum of 5°C (41°F) with a maximum of 10°C (50°F)

Cultivar Selection

Prepared corms are readily available in single colours or as mixes of single and double flowers.

There are a number of freesia species listed in the RHS Find a Plant. Bulb specialist R. V. Rogers lists a selection.

Problems

Heat damage: Temperatures above 15°C will result in spindly growth and quickly fading blooms. Excessive temperature fluctuations may cause deformed flowers which include separation of the first flower from the others by a long length of flowering stem; vertical, instead of angled flower head; ‘wheat ear’ appearance, caused by excessive elongation of flower bracts.

Frost damage: Depending on the severity of the frost, leaves may turn grey and translucent, then collapse or softening of the flower stem and collapse of flowers.

Pests: Susceptible to aphids, caterpillars and glasshouse red spider mite and mice and voles.

Diseases: Fusarium bulb rot, freesia mosaic virus and gladiolus dry rot fungus (Sclerotinia) can occasionally be encountered.

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