Table 1.

Effects of cottonwood and silver maple roots on growth of ground covers.

		With cottonwood	Control without tree roots	% Change	with silver maple	Control without tree roots	% Change
English ivy	Tops g	46	83	-44%	68	86	-21% NS
	Roots g	5	13	-60%	9	11	-18% NS
Liriope	Tops	37	61	-38%	63	68	-7% NS
	Roots	23	33	-32%	42	50	-16% NS
	Tubers				14	5	-28%
Dwarf bamboo	Tops	6	8	25% NS	4	4	No Change
	Roots	14	17	-20% NS	16	29	-43%
	Rhizomes				18	35	-50%