Gunnera x cryptica (Giant Rhubarb, Gunnera)

Michael's Opinion

I wish I was in a warmer climate where I could grow this plant. As a child growing up in Cornwall, England, this plant was common in the large estate gardens but to a child's eye was not appreciated horticulturally; although because of its immense stature it was fun to play amongst. A South American native, it requires lots of moisture and is often found growing in boggy situations. Those on the west coast can enjoy this plant, although late frosts may be a concern for them and thus often some form of protection may still be required. I have tried to grow it as a potted plant but the results were always rather pathetic.

Botanical Information

FamilyGunneraceae
GenusGunnera
Speciesx cryptica
Synonymsmanicata
CategoryPerennials, Tropicals
OriginG. x cryptica is a cross between G. manicta which is native to Brazil and Columbia and G. tinctoria. It was once thought that the plants commonly found in United Kingdom gardens were G. manicata, but are actually the hybrid G. x crpytica.

Details

USDA Hardiness Zone7-10
USDA Hardiness Ref.
Canadian Hardiness Zone8
Canada Hardiness Ref.
RHS Hardiness ZoneH2 - H6
RHS Hardiness Ref.
Temperature (°C)-18 to -5
Temperature (°F)0 - 40
Height2 - 3 m
Spread2.5 - 4 m
GrowthFast
Flowering PeriodJune, July

Description and Growing Information

General DescriptionThe broad leaves provide excellent ground cover along ponds. The bright green leaves are contrasted by the yellow and red flowers.
ShapeSpreading and clumping habit.
LandscapeGround cover in moist, large open areas protected from extreme cold.
PropagationPropagated from seed. Germination is slow and requires protection from frost or clump division.
CultivationBest grown in rich, consistently moist soils and part-shade in a protected location. In areas of persistent frosts, wrapping the crown in winter with straw or folding the dyings leaves over the plant will afford some protection.
Notable SpecimensGlendurgan Gardens, Falmouth, Cornwall, United Kingdom. Trebah Garden Trust, Mawnan Smith, Falmouth, Cornwall, United Kingdom. National Trust Trelissick Garden, Feock, near Truro, Cornwall, United Kingdom. Burncoose Nursery and Gardens, Gwennap, Redruth, Cornwall, England.
HabitatFound in areas with consistently moist soils; along the banks of lakes, rivers and streams.
Leaf DescriptionThe large, green leaves are 2-3 m long, with toothed palmate margins and prominent veins. The leaves have small, prickly red hairs.
Flower DescriptionSmall, reddish green flowers.
Fruit DescriptionThe berry-like fruit is small and red.

Photographs