Morris Arboretum

Up On the Roof

Louise Clarke, Aerial Gardener

Tradescantia ohiensis

Ohio spiderwort is an eastern North American perennial that blooms from May through July on the arboretum’s intensive green roof. Remembering this as a shady resident of my mother’s garden, I was skeptical of its performance on a green roof.

Spiderwort has adapted to the roof’s sunny, hot and dry growing conditions with aplomb. Its three-petaled blue flowers last only one day, like miniature daylilies. It receives no special care, other than being cut back in mid-summer after its blooms are spent. With adequate moisture, it may provide a second flush of flowers for fall. In garden beds Tradescantia may grow to 3’, but its stature is reduced on the green roof due to less moisture and leaner soil.