By Skip Richter
winter is a good time to do some cleanup work in your
perennial beds around the landscape. A little sprucing
up now will pay off in a much more beautiful landscape
during the coming season.
The term perennial can
correctly be applied to any plant that returns for more
than two years. This would include shrubs and trees.
However. when we say perennial we usually mean plants
that die back to underground structures each winter and
return the following spring. These plants are more
specifically known as herbaceous perennials.
Sometimes also included in the general term perennials
are certain herbaceous evergreen plants that don't die
back in the winter, such as cast-iron plant. The term is
also applied to plants that are rather woody near the
base that also don't die back completely in your
particular growing zone but which may be cut back like a
perennial. An example would be a subshrub such as
I should also point out that
Texas is one big state. What is perennial in central or
southeast Texas may be an annual in the metroplex or the
Panhandle. Therefore some adjustments may need to be
made as I refer to specific plants as perennials.
For the sake of this article, I will be using the
term perennial in this broader sense of including all
these plants that die back to the ground in winter and
others that don't but may be cut back at this time. Here
are a few tips to help you get the various types of
perennial plants around your garden in top shape for
hard freeze will kill back the top growth of flowering
perennials such as cannas, Mexican bush sage (Salvia
leucantha), various penstemons, lantana, cigar plant
(Cuphea ignea), Mexican mint marigold (Tagetes
lucida) and various types of ginger. Cut these
plants back to near the ground and chop up the top
growth for use in mulching or to include in your compost
Even if the top has not been completely
killed to the ground, it is usually a good idea to cut
them back since some freeze damage may have occurred in
lower areas, and cutting back will provide for a more
attractive plant in spring when fresh new growth
If a species is marginally hardy in your
area, pile the mulch up several inches over the base of
the plant to provide a little extra protection from late
cold snaps. Yellow bells or esperanza (Tecoma stans)
and butterfly ginger (Hedychium) are two examples
of plants not dependably hardy throughout Texas.
Perennials that bloom in the summer and fall are best
divided in late winter and early spring. Dig the clumps
and use a sharp butcher knife or Japanese Hori-Hori
knife to cut them into sections for resetting them in
your garden beds. Replant the sections at the same depth
they were previously growing and water them in well.
Then mulch the soil around the plants.
This gardening term generally refers to
plants that are woody at the base but that may partially
die back in winter. Examples include autumn or cherry
sage (Salvia greggii) and skeleton-leaf goldeneye
These plants have
characteristics and growth habits somewhere between what
we think of as woody shrubs and herbaceous perennials.
They are often treated more like shrubs or simply left
unpruned, resulting in a rangy, unattractive appearance.
Cherry sage takes on a more open, woody appearance and
does not bloom as well when left unpruned.
plants should be cut back to 6 to 10 inches high
depending on the species. They will resume growth in
spring, creating fuller, more compact plants without all
the old woody growth. Cherry Sage blooms much more
profusely this way. By early summer it will be starting
to get rather lanky and its blooms will be fewer atop
long spent bloom stalks. That is a time to shear it back
by one third, apply a little fertilizer and water it in
well to bring on fresh new growth and more blooms.
Evergreen Herbaceous Groundcovers
stays green year-round and is often left untrimmed from
year to year. After a long hot summer or cold winter it
can start looking pretty ragged. It's a good idea to cut
it back to 2 or 3 inches tall in mid-to-late winter.
Your lawn mower or string trimmer can be used for this
Don't wait too long to do this because
liriope will begin its growth very early in the spring
and a late trimming will result in ragged tips on the
newly emerging foliage. Mondo grass can also be sheared
back when it starts looking less attractive.
Vining ground covers, including Asian jasmine, vinca,
wedelia, wooly stemodia and ivy, may be left unpruned
most years. However, if the plants begin to look worse
for the wear they can be cut back to a few inches high
with a mower or string trimmer, although this is no easy
task. After being cut back, the plants will put on fresh
new growth with the arrival of warmer spring weather.
Cast-iron plant can also become unattractive after
long hot summers and cold winters. Prune out the old
stalks just above the ground in late winter using hand
pruners. New growth will soon fill in, creating a fresh,
When you've completed this
late winter pruning you may want to go ahead and divide
some of these clumping ground covers. Dig up the plants
and split the clumps into sections with a sharp spade.
You can push two spading forks into the clump back to
back and then push the handles apart to pry the clump
apart. Then reset the plants and water them in well.
We have many beautiful
types of ornamental grasses in our landscapes. Clumping
ornamental grasses, including various types of
miscanthus and pennisetum, are attractive throughout the
growing season. Their seed heads, which appear in late
summer, are especially attractive. I prefer to leave
them unpruned through the winter season when the straw
colored clumps still serve an ornamental purpose,
especially on a frosty morning when ice crystals form on
the seed heads and arching foliage.
Prior to the
arrival of new growth in early spring, these clumps
should be cut back to within 6 to 10 inches of the soil
line. If left unpruned, the old dead growth will detract
from the attractiveness of the fresh new growth. However
pruning ornamental grasses can be quite a chore!
Some gardeners use a pair of hand pruners or loppers to
prune their ornamental grasses. With sharp tools as well
as some time and patience this will work. Others report
that a string trimmer with a brush blade works well.
One Extension bulletin from the southeast suggests
wrapping two strips of twine or two bungee cords very
tightly around the clump, one at ground level and the
other a few inches above it. Then use a reciprocating
saw or a chain saw to cut the stalks between the two
restraints. I've not tried this technique, but it does
sound interesting! I would suggest taking it slow as
some grasses can clog up the chain housing on a chain
saw if you proceed too rapidly.
often is left unpruned and becomes quite unattractive.
Its sharp leaves and incredibly tough stem and leaf
tissues make pruning extremely difficult. Have a sharp
pair of loppers and wear protective eye glasses, a long
sleeved shirt and gloves to protect yourself if you try
to take on a clump of pampas grass!
After a few
years, ornamental grasses can begin to develop a dead
center as the clump spreads outward. At this point they
need to be divided and reset to maintain an attractive
appearance. Dividing grass clumps is not an easy task
because they are extremely tough.
digging the grass plant up completely. Then use a sharp
spade to cut the clump into sections for replanting. A
machete or sharp butcher knife may also be used to
divide the grass clump. Don't be afraid of harming the
grass plants as they are quite resilient. Discard the
dead center of the clump into the compost pile. Then
reset the grass divisions and water them in well. They
will take off growing rapidly with the arrival of warm
weather. You may want to pot up some of the extra
divisions for sharing with friends or planting elsewhere
in your landscape.
Other Tips for Perennial
Late winter is a good time to plant or to
re-plant perennials in a new location. Perhaps you have
a few plants that struggled in too much sun or shade
this past year. Maybe there are some that needed to be
in a better drained bed or where they could receive more
moisture. Now is a good time to dig those plants,
prepare the garden beds and then reset them in their new
Make sure to mulch all your perennial
beds well. Mulch prevents weed seeds from germinating,
protects the soil surface from crusting and erosion,
moderates soil temperatures including winter cold and
summer heat, and gives a garden bed a more attractive
Don't throw all those trimmings from
your perennial plants away. They are organic matter and
therefore contain nutrients that will be released as
they decompose in a compost pile. They can also be
chopped up and used as mulch or as pathway material.
As the perennial plants in your landscape begin to
grow in the spring, apply a moderate application of
fertilizer around the plants. Scratch it into the soil
surface and then water it in well. This will provide a
boost for the growing plants, ensuring good vigor and,
in the case of flowering plants, good bloom production.
If you have aged manure to use around the plants, go
ahead and apply it in the winter because it will
gradually break down and release its nutrients as the
soil warms up and microbial activity increases.