This bit of garden had terrible weed problems and last summer I hit it with round up and a dug it over (something I rarely do here) consequently it was a large patch of bare earth in the spring so I bunged in all the pot fulls that were sitting around waiting for replacements as they had run out of steam. Its actually not looking too bad! a bit more rain may have helped.
I will have to think of something for next year (not expecting some of the plants to survive/do anything for next season)
Charlie, I split mine in the spring when things are just beginning to warm up and the Colocasias are beginning to grow again (I assume that what you call 'Black Stem' is C.fontanesii?).
I find that planted out they love muck and water, they are even happy when the muck is fresh from the horses bum.
But why would you want to split it? They are so easy from the runners. If you would like more let me know, they are a weed in the tunnel here; the runners get between pots and form new plants when I'm not watching!
Any you want shot of I can re home here :) , I have three areas I want to try it (and mine is in a pot, without soil the runners don't venture far and most re root in the pot)
Ah, ponds and big leafed plants, fantastic. The following 4 pictures are from a garden called St Martins Manor (its near Fowey) went there as part of a HPS visit in 2002 and it was this garden that sparked my interest in the "sub tropical look" trouble is I don't have the wet soil in summer to pull it off (doesn't stop me trying!)
Ken Olson the owner is the tall guy in the first picture stmartins5 by charliepridham, on Flickr
Not sure what the plant is (it was some time ago now) could be Thalia? tried that here it lingered for a few years before doing a Cheshire cat impression