I have this vine and except for the dead leaves that collect in the wire canopy (it's in my kitty habitat), I have no problem with undergrowth. What I don't like about this vine is that it is a huge magnet for spider mites. Every summer, there's an invasion that all but decimates the vine unless I hit it with a hard spray of water nearly every day.
Alan, I envy your passie success. I have not been able to keep one alive long enough to enjoy many blooms. IMO, they are definitely more finicky than the vigna caracalla.
