I figure that plants that spread aggressively by runners have a better chance of doing well under a canopy of a maple. I have a pond on the outer edge of the canopy of two 100+ ft silver maples and other deciduous trees and I’d like to plant some water themed plants around the pond. I have houttuynia cordata, petasites japonicus var. giganteus, and oenanthera javanica that I want to plant around the pond. Even though they won’t be in contact with the water I want my pond to look natural by having plants that grow naturally near water. So question is, since they are naturally very aggressive spreaders, if I plant it in the outer edge canopy of the maples won‘t they behave better? Of course I will water them more than any other garden in my yard.