Grasses
pruning Although ornamental
grasses generally don’t require cutting
back for the health of the plant, most
will benefit from cutting back once a
year, if for nothing but aesthetics.
Grasses that aren’t cut back in the
spring may be slower to start new
growth, since the old foliage will
impede the sun from hitting and
warming the crown of the plant.
Most grasses should be cut back just
before new growth begins in the
spring; this is normally mid-March to
early April in the Midwest or late
February to early March in milder
areas. Cool-season grasses like
calamagrostis break before
warm-season grasses like miscanthus
and will need to be cut back earlier.
Certain grasses such as festuca may not
need cutting back at all, only removal
of dead leaves by hand. Some garden-
ers choose to cut their grasses down in
autumn if the plants tend to fall over or
lose their color in winter, or if time is
limited in the spring; however, besides
offering outstanding winter interest,
dormant foliage left standing on the
plants often provides additional winter
protection to the crown against cold
and excess moisture to help prevent
winter losses. In some dry climates
where dormant grasses may be a fire
hazard, cutting them back is the law.
Cut most grasses down to within
3–4 in. of the ground. Certain grasses,
particularly those that are inclined to
be short-lived, resent close shearing
and may not recover if cut down closer
than 3–4 in. Tying the grass together
with heavy twine before cutting can
help tremendously with cleanup. Once
it is cut at the base, the bundle can be
easily transported to the compost pile.
It also helps if two people are working
together. Wear gloves and long sleeves
as well as safety goggles when cutting
back, as grass blades can be razor-
sharp. Hand pruners can be used on a
small-scale planting, or handheld
hedge shears, electric hedge shears, a
weedeater with a blade, or even a chain
saw may be the tool of choice. As the
size of the planting increases, so can
the intensity of the tool used. I find
electric hedge shears to be the most
useful.
Deadheading may be necessary on
spring-blooming grasses if the heads
shatter or become unattractive later in
the summer. Deadheading also
reduces seeding on grasses so inclined.
Some people feel that the flowers of
certain grasses, such as blue fescue
(Festuca glauca), only detract from the
foliage, in which case the panicles can
be removed before flowering occurs.
Some grasses, such as variegated
forms of miscanthus, have a tendency
to flop and need staking. Cutting
grasses down to 3–4 in. above the
ground in June or July can reduce their
height, eliminate the need for staking,
and possibly put a large-growing grass
more in scale with the rest of the
planting. It may also cause a delay in
flowering, depending on the species.
Bob Saul of Saul Nursery in Georgia
cuts variegated miscanthus down to 4
in. in early July when plants are 5 ft.
tall. The results of such pruning are
plants that mature at an upright 2 1/2–3
ft. rather than a flopping 6 ft. In the
Midwest I cut plants down to 18 in. in
early July, and they grow to 5 ft. within
2 weeks—obviously cutting down
lower is in order. This is an area where
more experimentation is needed.
other maintenance Most grasses
prefer full sun, although some tolerate
shade. Grasses benefit from a
high-organic, well-prepared soil. It
generally is best to plant in early spring
or early autumn to allow them time to
establish before the heat of summer or
the cold of winter. Keep new plantings
moist. Grasses are not heavy feeders,
and overly rich or high-nitrogen soils
can cause floppy growth and increase
the need for staking.
Grasses normally don’t require
division for about 5–7 years after
planting. Division is best performed as
the new growth emerges in the spring,
although grasses will tolerate division
at other times. Division can be
difficult, often requiring the assistance