This time of year is late for planting, as roots have limited time to start getting established before the soil surface starts to freeze (or experience freeze-thaw cycles, which can heave unrooted plants out of the ground and kill them). While most species can be planted now with regards to air and soil temperature trends (as soil cools-down much more slowly than air and allows roots to keep growing for a while after above-ground growth has stopped), early autumn is the ideal time to install perennials, shrubs, and trees, because it allows them to establish faster and to a greater extent before dormancy. Anything evergreen (for example, Mountain-laurel, Inkberry, or American Holly) is best put on hold until spring, as evergreens face a higher risk of desiccation damage if they can't get enough roots established by winter, since their retained leaves will keep losing moisture all winter long.

Gardeners can still plant deciduous species now (though we do not have a reference list), but as with any new planting (regardless of time of year), they will need careful attention to watering needs. Use the same approach as would be used during summer, which is to feel the soil around four to six inches deep; if it has become somewhat dry to the touch at that depth, water thoroughly. That might be a challenge to monitor or irrigate once we start to freeze, however, which is another reason that late-season plant installations can be harder to manage. Still, mulch them well (be sure not to cover the crowns or bury main stems) in order to insulate the soil surface.

Miri