Some perennials can flower themselves to exhaustion and are then unable to
form buds for the following year. To prevent this from occurring, the whole plant
should be cut back to stimulate vegetative growth. This principle applies to a
wide range of perennials. New growth produced from cutting back a plant early
in the season is more vigorous and less stressed than the old dying foliage and is
thus less likely to succumb to disease and weather damage.Stagger plant heights or bloom times
For perennials growing in large groups, you can encourage the plants to mature
to differing heights or to bloom at slightly different times by pinching or cutting
back. This creates interesting gradations and extends the bloom time of a
planting. You can delay flowering on a few stems of an individual plant to
provide a longer bloom period at the expense of abundance.Reduce plant height
Reducing plant height, thus eliminating the need for staking, is an important
pruning principle. The little bit of time it takes you to cut back or pinch perenni-
als before they flower, creating more compact plants, will save you the headache
and time of having to stake plants later.Keep plants in their own space
I like full, lush (some might call it crammed) gardens with as little ground or
mulch showing and as diverse a palette of plants as possible. Such an approach
requires some management of the planting to keep everyone in their own space.
Sometimes this will mean the removal of a branch or several at the base of the
plant or a few panicles off the top. (Panicles are branched groups of flowers on a
single stem.) Other times it means cutting the whole plant down to the ground,
after its show is finished, to let its neighbor have room to shine. Intricate gardens(left) Regrowth and flowering
on Malva sylvestris ‘Zebrina’
after being cut down to 8 in.
following the initial bloom
period.
(right) Balloon flower
(Platycodon grandiflorus)
responds well to cutting back
before flowering to reduce
height and eliminate the need
for staking. These pruned plants
matured to 18 in., compared to
the normal height of 2 to 3 ft.
88 PruninG Perennials