Are V. tortifolia and V. spiralis totally different plants or subspecies? I have V. spiralis (the staight type) growing like a weed, 40" long, runners etc etc. (after only a couple of months) My V. tortifolia (corkscrew) OTOH, does not seem to grow very much at all. Any ideas as to the cause? <<<<<<<<<<<<<<<<<<Spug (Sparrow) London, UK.>>>>>>>>>>>>>>>>>>>>