any perennial including liriope and ornamental grasses can
be cut to ground level at any time, usually fall or spring.
In the early spring (prior to April 1st), cut back all perennials
including liriope and ornamental grasses as close to the
ground as possible. Exceptions would be russian sage
(cut back to 4-6”) and evergreen perennials like lavender,
dianthus, etc which should removed of dead stems and perhaps
pruned back slightly for shape.
When fall arrives, if a perennial does not look good, cut
it to the ground. However, some perennials (liriope,
grasses, sedum, russian sage) look nice even though they
are dried out during the winter months and can be left to
cut back in spring.
During the growing season, cut back spent flowers as necessary. Purple
Coneflower and Daisies need to be deadheaded (old blossoms
removed back to where new flower bud is forming) to encourage
more blooms. Yarrow and Salvia(meadow sage) should
definitely be removed of old flowers as both of these will
rebloom later in the season. Floppy perennials such
as Autumn Joy Sedum and hardy chrysanthemums should be “pinched”
or cutback 2-3 times prior to early July.
Lastly, Lambsear and some Hosta are plants that are grown
for their foliage. You can remove the flower buds
if you don’t like them. A good pair of gas or electric
pruning shears are ideal for cutbacks but a good pair of
sharp hedge shears will suffice. Hand pruners should
be used for all other pruning.
Cutback Shrubs (spirea, bluemist shrub, crimson
pygmy barberry, st. johns wort) – cutback in spring
to a rounded, slightly dome-topped mound between 8”
and 18”. This will keep the plant from becoming
too large during the growing season and give it a neat appearance.
You will find yourself modifying your cutbacks as you familiarize
yourself with the growth rates of individual plants.
Carefree Roses – cutback in spring or fall
to an 18” size (carefree wonder is generally and upright
shrub to4-5’high x 3’ wide and carefree delight
is a sprawling plant 4-5’ wide x 3’ high).
Butterflybush – cutback to 12-18” (this
maybe difficult the first year, but don’t worry they
never fail to grow 6’ every year!).
Annabelle Hydrangea – cut to ground level
every year in spring (those dried blooms look nice through
Lace Cap and Blue Snowball-type Hydrangeas –
Leave Alone, pruning will result in the removal of the flower
buds and you will have no flowers. You can cutoff
up to 1/3rd of the plant if it is growing too large or for
shape and still retain some flowers.
Oakleaf Hydrangea – generally leave alone,
if it needs shaping, prune right after flowering.
Other Deciduous Shrubs – prune after flowering.
Flowering Evergreens (azaleas, rhododendrons, etc.)
– prune after flowering.
Evergreens – prune anytime.
An application of granular pre-emergent herbicide is a good
idea to control annual weeds in the early spring prior to
mulching and can also be of benefit over paved areas to
prevent weeds appearing in the cracks. Treflan, Eptam,
Preen, etc. are all brand names (always apply per directions). Yellow
Nutsedge is not affected by pre-emergent herbicides and
should be pulled immediately being sure to extract all their
roots. Use concentrated Roundup herbicide per directions
to control perennial weeds (thistle, dandelion, morning
glory, wild chrysanthemum, and poison ivy).
An application of granular 5-10-5 is recommended prior to
Edge all beds with a sharp spade and apply 1⁄2 to
1” layer of new mulch every year.