Start gunnera from a side crown in spring, and keep it moist. Fresh seed on the surface is slower, and the seedling needs a frost-free winter before you plant it out.
Cut a side crown in spring, and keep it moist
| Factor | Recommended | Avoid |
|---|---|---|
| When | April or May, before the giant leaves are fully up | Do not wait until the clump is too heavy to reach |
| Piece | A side crown with roots, cut from the edge | Do not try to lift the whole clump |
| Pot | Pot it at once in a fibrous mix, and keep it moist and shaded | Do not let a new piece dry in the sun |
| Aftercare | Grow it moist through the first season, frost-free if it is still small | Do not plant a weak piece into a dry border |
Gunnera makes small extra crowns around an old clump. The parent is often too large to dig and split the way you would a hosta, so cut a rooted piece from the edge in April or May, pot it, and keep it moist and shaded until it holds. [1] [2] A bare, shaken scrap dries before it can take. Grow the new plant on in a pot if you need to move it for frost, then plant it into wet ground the next spring. [3] [4]
- In April or May, find a side crown that already has roots. Wear gloves — the stalks are prickly.
- Cut that piece from the edge with a sharp spade. Leave the main clump in place.
- Pot it at once in a fibrous mix, at the same depth. Water it in, and keep it moist and shaded.
- Grow it through the first season. If it is still small, keep it frost-free, then plant it into wet ground after frost.
How do I start a new plant?
Cut a rooted side crown in April or May, pot it, and keep it moist and shaded. Do not try to lift the whole clump.
Sow fresh seed on the surface, and keep it frost-free
Sow seed as soon as it is ripe, or keep bought seed cold in the packet until spring. Sow one seed on moist mix, and cover it only with a thin grit so light still reaches it. Keep it moist and warm, about 68 to 77 F, under a cover. Seedlings may take two to eight weeks. Grow them in shade, never let the mix dry, and keep them frost-free through the first winter. Plant them out after frost the following spring. Read How to Grow Gunnera if you still need the wet bed.
- Sow fresh seed. Do not store it dry on a shelf for a year and hope.
- Press it onto moist mix. Cover it only with a thin grit. Do not bury it deep.
- Keep the mix moist and warm under a cover until it sprouts, then grow it in shade.
- Keep the seedling frost-free through the first winter. Plant it out after frost, into wet ground.
How do I sow the seed?
Sow fresh seed on the surface of moist mix, keep it warm and humid, then grow the seedling frost-free through the first winter.
If you need more plants, cut a side crown in spring and keep it moist, then grow it shaded until it holds.
FAQ
Can I lift the whole clump?
A mature clump is usually too heavy. Cut a rooted side crown from the edge instead.
Can I root a leaf stalk?
A leaf stalk without a crown rarely makes a plant. Take a side crown with roots, or sow fresh seed.
Related guides
Recommended plants
References
- [1] The Garden of Eaden -
https://gardenofeaden.blogspot.com/2015/08/how-to-propagate-gunnera-manicata.html - [2] Elisabeth C. Miller Library -
https://depts.washington.edu/hortlib/pal/on-dividing-gunneras/ - [3] BBC Gardeners' World -
https://www.gardenersworld.com/how-to/grow-plants/how-to-grow-gunnera/ - [4] University of Arkansas Extension -
https://www.uaex.uada.edu/yard-garden/resource-library/plant-week/gunnera-1-4-13.aspx
This note is part of Gunnera Guides.
More notes on making another plant live in Propagating Guides.
Updated: Reviewed by Bosquelle Editors