Black walnut tree and sedge compatibility
I am going to gradually replace much of the "lawn" in my backyard with sedges of various kinds, and I want to begin with the difficult area under two large shade trees, a black walnut and a cottonwood (they are side-by-side in a sort of tree island at the side of my yard). Do sedges/caryxes generally grow under black walnuts? Also, my garden center suggested pachysandra for that site but I think it is considered invasive, yes?
Prince George's County Maryland
Sedges (Carex sp.) are tolerant of juglone, so they should be fine to plant in the area under your black walnut tree. http://www.johnson.k-state.edu/docs/lawn-and-garden/in-house-publications/trees-shrubs/Landscaping%2...
Japanese pachysandra (Pachysandra terminalis) is invasive in Maryland. Allegheny spurge (Pachysandra procumbens) is a native plant that could be used instead of the Japanese variety. https://extension.umd.edu/hgic/groundcover-list