Dividing Perennials
Most
perennials can be divided as soon as they are through blooming for the year.
Perennials need to be divided when
·
the
flowers are smaller than normal
·
the
stems fall over easily
·
there
are a large number of underdeveloped shoots
·
the
center of the clump is hollow and dead
·
the
bottom foliage is sparse and poor
Most
perennials need to be divided every three or four years, although some resent
being disturbed and should only be divided when necessary. A few species, such
as chrysanthemum, Monarda and Anthemis, do best if divided every
spring.
All
spring blooming plants as well as peonies, irises and oriental poppies can be
divided as soon as the blooms fade or in the fall. All others should be divided
in very early spring in zones 2-5 and in fall in warmer zones.
If
the weather has been very dry, water the plant thoroughly the day before you
divide. If possible, work on a cool, cloudy day or late in the evening to
reduce moisture loss.
To
divide a perennial, first dig around and under the entire plant and lifting it
carefully to avoid root damage. Gently shake the soil from the roots or rinse
the soil off with a gentle stream of water from a hose. Prune the top of the
plant to about six inches and remove damaged or diseased sections. Divisions
should be taken from the outer edges of the plant since this younger growth
will produce more vigorous plants. Some plants can be broken apart by hand, but
if necessary, use a sharp knife.
Make
sure each division has at least three vigorous shoots. Small shoots will take
longer to flower. Small divisions taken from a number of perennials can be
planted together in an "nursery bed" where they can be nurtured to
flowering size, then moved to the main flowerbed.
Replant
the divisions as quickly as possible, setting them at the same depth as the
parent plant. Water thoroughly and provide mulch to prevent the soil from
drying out. A layer of mulch will also protect the developing roots from frost.