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Growing Gunnera in zone 5b Ontario

Posted by glaswegian 5b, Ont (My Page) on
Sat, Apr 11, 09 at 18:45

Does anyone grow this mammoth plant in zone 5b? I purchased one this week and it wasn't cheap either at $18. What is the trick to growing it successfully?


Follow-Up Postings:

RE: Growing Gunnera in zone 5b Ontario

I've seen one growing at Toronto Botanical GArdens/Edwards garden(zone 6) and noted it thrived on wetness, lots of it. It was huge with umbrella sized leaves and it had spines too so be careful to plant away from high traffic areas.

RE: Growing Gunnera in zone 5b Ontario

It's tricky in zone 5, as it's not really hardy enough for here in and exceptionally cold winter. It will need a lot of mulch protection in winter and a deep snow fall. I had thought of growing one too, but planned to dig up the huge root ball and store it in the cold cellar for the winter. I have not known anyone who successfully overwintered it outdoors naturally in zone 5.

Let us know if it does survive the winter outside. Perhaps if you have a microclimate that is a bit warmer? Maybe against the house on the south side? Likes LOTS of water. Grows on the stream edge.

RE: Growing Gunnera in zone 5b Ontario

Hello Glaswegian
How did your Gunnera experiment go...??? I tried to grow by seed this year but had 0 germination. I would like to know where you purchased your plant, we have a sheltered location in a valley near Alliston.
The pic is last week in the Botanical Gardens in Edinborough
Best Regards

RE: Growing Gunnera in zone 5b Ontario

  • Posted by signet z6 S.W. Ont (My Page) on
    Tue, Oct 2, 12 at 13:14

I would suggest growing it in a pot in water . It needs full sun and constant wet soil and will grow quite huge Not knowing where you are located , it is impossible to tell you if it will grow in your location , It will if you grow it as an annual . I am zone 6 but much too dry to grow it ( SW Ontario ) It is tender even in zone 7 so my best guess is it will need to come inside for the winter. So yes it can be grown in zone 5 full sun totally wet all the time . easiest way is in a pot sunk into a pond or plant in a bog and either transport pot inside in fall or dig out of bog and set in a pot to take inside . It will need constant wet soil inside as well . I almost bought one from DeGroots a nursery in Sarnia until I went to pick it up and discovered it's suggested coolest zone was a zone 8. I asked them why they even bothered to stock it (of course they have a huge heated green house so they are ok . And of course the salesperson didnt know why they try to sell an item not rated for our zone) ...yeah right !
They will sell anything to anyone and if it doesnt survive all the better cuz then you are back looking for another one and they make money..... that is why they sell plants not rated for our zone .


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