Who is growing Gunnera manicata successfully?

Mine is planted by the steam, in a sunny position, and that's all I do, too. It is about the same size as yours, maybe a foot or two bigger all round. I can't say how places like Wisley get such enormous plants...Mine has been in considerably longer than three years, as it was here and just as big when we came.

I have G. manicata and G. tinctoria. Tinctoria is a smaller species and more of a clump former and i find it easy to grow, My manicata seems to be a bit fussy as well. It is in a damp position in sun and the soil is quite good.

My only thought is that they require a really deep, thick, rich, leaf mould filled soil in order for its fleshy roots to get through and also the nutrients it needs.

I cant find any specific data on there care but they do like feed, in the form of controlled release. But if its planted near a pond, you dont want the feed leaching into soil.

The trunks on the huge ones you see are about a foot thick and i'd imagine they have been there, esp at Wisley since it first opened decades as it opened is was given to RHS in 1903, but was a private garden before then. So as the old mature thick trunks aged and died off, the young generations of offspring have abviously got used to the weather and have the root run and tneder every day care they need.

Perhaps its best to cut the leaves in winter when they have gone brown, rather than green that i have seen some do, as this will put more food back into the bud as its called.

Thanks to both for the advice. I'd guess the need for a rich soil and more nutrients is the case, as the soil here by the pond and river is very poor. I'll try a slow release fertiliser next year and see if it makes a difference.
Merci,

NOt to much or else it may affect pond life

I think age is an important factor, Bertie. The big ones have a huge base structure beneath the leaves that must have taken years to develop.

Trouble is, when you get to retirement age (almost in my case), you get impatient. I know I should be planting oaks for our descendants in several hundred years time, but I do like quick results that we can see!
I rather liked a comment by Bob Flowerdew once who said he thought God would give you the chance to see any trees you plant flower and fruit at least once!
If that's true, then growing walnuts from seed must be a good way of staying alive as long as possible!

Hi Bertie, I have G. Manicata and tinctoria. I've had the Manicata for about 8 years now and its massive, this year it has done really well, it must be 10 feet across. Its next to my brook but I dont feed it. The soil there isnt that damp but as its close to a hedge, maybe it does feed off leaf mould. I found the tinctoria took longer to establish, they've been in around 6 years, they are by my pond, not on particularly good soil but the Spring was kind to them this year as normally they get frosted. Maybe its a matter of time before they get huge. We get lots of frosts here but I bend the leaves over the crown each autumn and that is enough to protect them through the winter. Good luck with yours.