Gunnera manicata

Gunnera is one of the biggest and most spectacular, architectural, herbaceous plants. Thought to be around 150 million years old and first introduced into Europe in the 1860′s it if often called Dinosaur Food or Giant Rhubarb due to its gigantic, deeply lobed, deep green leaves, which grow up to 2 metres (6ft) across.

The plants need a lot of space because it is difficult to restrict their size. They look best standing as specimen plants in a damp bog garden, or beside a large pond where the reflections reveal the undersides of the leaves. The stalks hold tiny red-brown flowers on erect panicles up to 1m (3ft) in height, followed by small red berry-like fruits.
The fat growth buds clustered in the crown are prone to frost damage, so pile the dead leaves and stems into a mound over the plants in autumn for winter protection.
Gunnera manicata is easy to grow. Good soil with steady moisture, by a pond or stream perhaps, and a great deal of space is all you need to enjoy this magnificent plant.

• Awarded the RHS Award of Garden Merit
  Gunnera manicata was awarded the Royal Horticultural Society’s Award of Garden Merit (AGM) in 1993.

Sowing: Sow seeds as soon as possible.
For maximum freshness, please keep seed refrigerated in its original packaging until you are ready to sow them.
Fill a large pot (see below) with fertile moisture retentive medium. Sow thinly and evenly distribute seed over surface (don't touch seed as skin oils interfere with germination).
Tamp into soil. Keep moist and mist often (a plastic cover greatly improves success) Provide bottom heat if possible, and ventilation.
Optimum germination temp: 20 to 25°C (68 to 77°F). 15 to 60 days to germination.
Do not let seed suffer temperatures of less than 10°C (50°F) otherwise germination will be delayed. Do not disturb seedlings for its first year.
Give dilute liquid fertiliser during growing season. Never let seedlings dry out or expose to full or direct sun.

Now…about that pot size …the plant growth after their first winter is incredible. Seedlings 3 to 4 cm in size will resemble rhubarb by the end of August. In order not to disturb the seedlings, you may wish to start the seeds off directly into a large container – perhaps a two gallon pot if you have one (Yes…that large!)
In the second year transplant to individual containers or seat in permanent site. Grow on in any good moist garden soil.

Cultivation:
Though considered hardy, Gunneras need special care in cold winter areas in order to survive. i.e. where winter temperatures are likely to drop below -5°C (20°F). Cut down all greenery in late October to 30cm (12in) of the root ball then place a thick layer of dry mulch over the crown for the winter. The mulch should be kept dry by a tarp or other rain proofing material. Remove mulch when last spring frost is past. A heavy mulch can help these plants survive to -17°C (0°F)

Plant Uses:
Architectural, Pond and Streams, Damp and Bog gardens.

Origin:
Gunnera manicata is native to south east Brazil and is thought to be around 150 million years old.
It was first introduced into Europe in the 1860′s by J.J Linden.

Nomenclature:
The genus name Gunnera is named after Johan Ernst Gunner (or Gunnerus) (1718-1773), a Norwegian botanist and founder of the Royal Norwegian Society. He was the author of Flora Norvegica and the first to suggest that since the northern lights were caused by the Sun, there also had to be auroras around the moon, Venus and Mercury
The species manicata is from the Latin meaning ‘having long sleeves’, possibly in reference to the hairy ‘trunks’.
It is commonly known as Giant Gunnera, Chile Rhubarb, Giant Rhubarb, Prickly Rhubarb or Dinosaur Food. Despite the common names, this plant is not closely related to rhubarb.