Fall is a good time to get ready for next year’s display of
spring-blooming perennials. Some may need repositioning, some
may have lost vigor as a result of crowding and some may be in
need of dividing. Most perennials will transplant easily in
October. Some root loss is inevitable, so the shorter, cooler
and rainier days of autumn are a less stressful time to move
plants. Since it’s not recommended to relocate perennials while
they’re flowering, species that bloom in late summer or fall
(Chrysanthemum, Sedum, etc.) are best moved in spring when the
first shoots emerge from the soil. When moving perennials, cut
them back, divide if necessary and include as much of the root
system as possible when digging. (As a rule of thumb, pull apart
fibrous-rooted perennials with your hands or using two garden
forks and cut apart the fleshy-rooted ones with a sharp knife or
spade.) When planting, be careful to maintain the same soil
level as their previous location (not planting either too deeply
or too high). Soak thorou