Gunnera

Gunnera flowers

A small group of hardy and half-hardy herbaceous perennials, grown mainly for their decorative foliage. Some species are large leafy giants and others are low growing creeping plants.

Family: Gunneraceae
Botanical Name: Gunnera (gun-e-ra)
Common Names: Giant rhubarb, prickly rhubarb

Foliage: Deciduous. Small kidney-shaped leaves or very large rhubarb-like leaves, depending on variety.

Flowers: Reddish-green flower-spikes.

Flowering Period: Summer.

Soil: Moist, poorly drained soil (clay or loam). Acid, alkaline or neutral pH.

Conditions: Full sun or partial shade. Plant in an east, west or south facing aspect, in a sheltered position.

Habit: Clump forming.

Type: Rhizomatous herbaceous perennial.

Origin: South America and Australasia.

Hardiness: Most varieties are reasonably hardy in the UK.

Planting and Growing Gunnera

Grow in an open, sunny site in a heavy moist soil with plenty of organic matter incorporated.

The large architectural forms make an impressive sight, with massive leaves on barbed stalks. Ideal in a boggy or damp part of the garden.

Taking Care of Gunnera

Water daily during growing season. Mulch large plants every spring.

Pruning Gunnera

Remove damaged leaves. Remove leaves of large leaf forms once they become blackened by frost and cover crowns for winter protection.

Pests and Diseases

Generally trouble free.

Propagating Gunnera

Divide established clumps in early spring. The large scaly buds of G. manicata can be removed from the rhizome and rooted. They can also be grown from seed but results can be poor and often take several years to reach full size.

Popular Varieties of Gunnera

Gunnera magellanica is a low growing, mat forming plant with kidney-shaped green leaves topped with short reddish-green flower-spikes. Suitable for a damp place or by pond. Height 3in (75mm). Available from Burncoose.

Gunnera manicata produces large, prickly, rhubarb-like leaves with red spiny stems. Large reddish-green flower-spikes. Height 6ft (1.8m) or more, spread to 10ft (3m). Needs a very large site by a pool or lake. For sale at Crocus. For sale at Thompson & Morgan.

Gunnera tinctoria (Chilean rhubarb) similar to G. manicata but with more rounded, deeply lobed leaves and shorter leaf stalks.