Regarding Arbor Vitae, Rushmore
Hello, We bought 30-40 trees 9 years ago and planted them in our yard. They have been thriving and growing, but we are noticing that quite a bit of the roots are starting to get exposed, possibly from slight soil erosion where they were planted as well as general growth. We are wondering if it would be better for the trees if we cover those exposed roots with dirt or wood chips, or should we just leave them be? They are Arbor Vitae (Rushmore). Thank you, Richard del Furia & Lisbeth Petersen
Hennepin County Minnesota
Unless the erosion is severe and/or progressive, doing nothing is an option. The arborvitae will adapt to slight changes in grade.
Otherwise cover the roots with 2-3 inches of mulch. Use shredded hardwood or something similar that won't float or blow away. It will be necessary to renew the mulch every two or three years to maintain its benefit.
Or plant ground covers such as pachysandra, lily of the valley, periwinkle or bishop's weed to cover the roots and stabilize the soil.