We have planted several gunnera on the west coast of VanIsle whose leaves are turning red, pics attached. We have had two die thus far while the others seemed to be thriving. Anyone have any experience with the symptoms? Thanks!
They are deciduous, so the leaves should be expected to die off at this time of year. Stack the withered leaves over the root crowns to help protect them from frost.
Thank you for your suggestion, but having raised Gunnera for some years I am familiar with fall senescence. Leaves turn brown; this is not it. Two plants have already died.
I've occasionally seen it happen with wild Gunneras down here when there is some kind of soil contamination. In both cases, the leaves turned red and then dropped off, and the plants died; when I had the soils tested I found all sorts of nasty things - arsenic, high levels of petroleum products, and traces of gold. So I got to make a really uncomfortable call to the park rangers about illegal mining inside their protected areas, and we had to plant water hyacinth in the areas to take out the heavy metals. Maybe have your soils looked at; I don't think it would be an illegal gold mine in your case, but the Gunneras do seem to be sensitive to petroleum.