How to Grow Galtonia Plants in your Garden

Gardener's HQ Guide to Growing Giant Summer Hyacinth

Galtonia species are usually grown from hardy bulbs in the garden and reach a height of between 90 cm and 1.2 metres.

They have a long blooming period from the middle of summer and throughout autumn.

When in bloom they carry white bell shaped flowers atop long upright stems.

Some common names of Galtonia include Summer Hyacinth and Giant Summer Hyacinth.

Galtonia candicans
Galtonia candicans by lilli2de.

Galtonia Growing and Care Guide

Common Names: Giant Summer Hyacinth, Summer Hyacinth, Cape Hyacinth, Spire Lily.
Life Cycle: Hardy perennial.
Height: 24 to 48 inches (60 to 120cm).
Native: Southern Africa.
Growing Region: Zones 6 to 10. As an annual in cooler areas.
Flowers: Middle of summer and autumn.
Flower Details: White, cream. Bell-shaped. Fragrant.
Foliage: Straplike. Linear. Grey-green. Dark green.
Growing Outside: Usually grown from bulbs as seed grown plants will not bear flowers for about five years.
Galtonia Bulbs: 5 to 6 inches (12 to 15 cm). Start of spring. Spacing; Small 6 to 8 inches (15 to 20 cm); Large 14 to 18 inches (35 to 45 cm).
Seeds: Cover. Start of spring through to the summer.
Sow Inside: Germination time: two to three weeks. Temperature: 70°F (21°C).
Seven or eight weeks in advance. Transplant outdoors early in spring or in autumn.
Requirements and care: Full sunlight to slight shade. Good drainage. Moist soil. Regular watering during dry periods. Winter mulch. Bring indoors over the winter and store in a dry and cool place in cooler regions. Propagate: offsets can be planted in early spring or towards the end of autumn.

How to Grow Summer Hyacinth - Galtonia

For quicker results you should grow summer hyacinth from bulbs as seed grown summer hyacinth can take as long as five years before they will first flower.

The bulbs should be planted about 12 to 15 cm deep at the start of spring. If growing from seed then sow in spring or summer and lightly cover the seed. The spacing of Galtonia plants is species dependent, plant small Galtonia varieties from 15 to 20 cm apart and tall ones about 40 to 50 cm apart.

Ideally summer hyacinth should be grown in a sunny part of the garden that had good drainage and a moist soil.

If you start Galtonia species off indoors from seeds then start about 7 or 8 weeks in advance. It should take two or three weeks for seeds to germinate at a temperature of about 20°C. Transplant Galtonia out in the garden in autumn or at the start of spring.

Caring for Galtonia plants in the Garden

It is pretty easy to look after Galtonia species such as giant summer hyacinth; they like a moist soil so keep well watered in dry periods; if you live in a very cold area it is a good idea to bring bulbs inside during the winter.

If you require more Galtonia plants for your garden then propagate Summer hyacinth by planting the offsets that they produce; this can be done in autumn or spring.

I hope that you enjoyed this guide on how to grow Galtonia plants. Updated September 2020.