EARLY SPRING PRUNING
Generally speaking, plants that are not pruned in the autumn need to be cut
back, or possibly deadleafed, in the spring. Perennials like species of Asarum,
Bergenia, Helleborus, and Heuchera need to have their dead leaves removed,
particularly if they have been exposed to windburn or sunscald. Epimedium
and helleborus need to be cut back early in spring so that the new flowers and
leaves are not masked by the previous season’s tattered remains. Rotary mowers
can be used on large plantings of epimedium. The groundcover Liriope spicata
also can be mown down in the spring. Moss phlox (Phlox subulata) may incur
dead branches over the winter, or portions of the plant may die out, and these
should be removed at this time. Evergreens may not need any additional
pruning in the spring in some years, as their foliage can stay fresh over the
winter. Phlox stolonifera and Dianthus gratianopolitanus are a couple that usually
fair well. Most often, evergreen basal foliage doesn’t need any additional
pruning in the spring.
Certain subshrubs have their overwintering buds aboveground, which
classifies them botanically as woody plants, but horticulturally they are classified
with herbaceous perennials. They benefit from snow cover for protection and
may experience tip dieback on the part of the plant above the snow line. Spring is
the time to prune off those dead tips. This group includes evergreen candytuft
(Iberis sempervirens), lavender, germander, and thyme. They may also need a hard
cutting back in the spring if they start to grow leggy. Lavender normally only
needs its dead tips cut off in late spring or early summer, once all the woody
growth has had a chance to break. Often the beginning gardener will prune back
lavender hard before winter, only to be disappointed that it doesn’t return at all
the following spring. Lavender may need a hard cutting back (down to 4–6 in.) in
spring every 2–3 years to hold a decent habit if it has become open and leggy, or if
it’s being used as a hedge. It can be cut back hard annually for hedging. Perovskia
can be cut to the ground to encourage sturdier plants; I prefer to cut mine down
to live buds, which can be 6 in. or more aboveground.
Electric hedge shears work best for ornamental grasses on large jobs. First tie
the grasses together, which keeps excessive debris to a minimum, and then cut it
down. It helps to have two people working together on this. Handheld hedgeSedum ‘Autumn Joy’ being cut
down in the spring. Note the
light green nubs of new growth
at the base of the plant.
134 PruninG Perennials