Perennial
Gunnera × cryptica
Giant rhubarb
Also known as: Gunnera manicata (of gardens, misapplied)
A colossal, umbrella-leaved perennial widely sold in the past as 'Gunnera manicata', now restricted in the UK as an invasive species.
- Full sun, Partial shade
- 1.5–2.5 m (5–8 ft)
- 3–4 m (10–13 ft)
- H5 · Zone 7
- June–July
- Deciduous
Overview
This is the giant-leaved gunnera most commonly seen in UK gardens under the name Gunnera manicata; research has shown almost all of that stock is actually this hybrid between G. manicata and the banned G. tinctoria. Rounded, deeply lobed leaves 1-2m wide rise on stout, prickly stalks, with dense reddish-brown flower spikes in summer. Because it can spread invasively, it is illegal in the UK to plant it out or cause it to grow in the wild, and it can no longer be sold; gardens that already have an established plant are not required to remove it, but should prevent it seeding or spreading and dispose of any waste material responsibly. NOTE FOR REVIEW: confirm current legal status before publishing this entry on the live site.
At a Glance
Growing Conditions
Aspect Suitability
- East-facing
- South-facing
- West-facing
Site Tolerance
- Wet soil
Soil Tolerance
- Clay
- Loam
- Acid
- Neutral pH
Foliage
- Architectural foliage
Foliage interest: May–October
Seasonal Timeline
- Flowering Jun Jul
- Foliage May Jun Jul Aug Sep Oct
- Fruiting Aug Sep
- Propagate Mar Apr
Maintenance Calendar
- Mar Check the crown has survived winter protection before uncovering
- Apr Feed generously as new leaves unfurl
- Jun Keep the root area permanently moist through summer
- Aug Remove flower spikes before seed sets to limit self-seeding
- Nov Cover the dormant crown with its own cut leaves or a deep mulch
Garden Design
Works well in: Bog, Pondside, Specimen, Tropical, Tropical / Exotic, Woodland
Needs a huge amount of space and permanently moist ground beside a large pond or stream to look its best. Because of its invasive status in the UK, this is a plant for existing, well-established gardens rather than new plantings - check current legislation before including it in any design or plant list.
Companion planting: Ferns, Moisture-loving perennials, Waterside grasses
Wildlife Value
- Shelter
Safety
- Skin irritant
Leaf stalks and the undersides of leaves are covered in sharp prickles; wear gloves and long sleeves when working near it. IMPORTANT: this plant (and anything sold as 'Gunnera manicata') is restricted in the UK - it must not be planted or allowed to spread in the wild, and is banned from sale. Confirm current RHS and GB Non-Native Species Secretariat guidance before publishing or recommending it.