PlantinG and renovation 57
Identifying the beast as annual, biennial, or perennial and its growth habit as
stoloniferous, rhizomatous, or clump forming is necessary for developing the
proper battle plan. Annuals generally last 1 season, then die; a biennial com-
pletes its life cycle in 2 seasons, then dies; a perennial normally survives for 3 or
more seasons. A stolon is a horizontal stem above or just below the ground that
forms roots at its tip to produce new plants; stoloniferous plants bear these.
Rhizomes are horizontal underground stems that have nodes (points on a stem
where leaves are attached), buds, or scalelike leaves and often are enlarged for
food storage. Clump-forming plants divide and fill in open areas, developing an
extensive root system.
Pre-emergent herbicides such as DCPA (Dacthal) or trifluraline (Preen) are
sometimes used on perennial plantings for control of annual weed seeds. The
problem with these herbicides is that they are species-specific as to which
perennials on which they are safe to use. In diverse plantings, there is the risk
of injury.
Careful application of glyphosate (Roundup) using a paintbrush can be
effective on perennial weeds. I also know of gardeners who prefer a technique
that involves wearing a cotton glove over a plastic glove, dipping the cotton glove
in the herbicide, and then wiping the growing tips of weeds with the glove.
Most of the time I simply weed by hand. I like to use what’s referred to as a
Japanese weeding knife, which works really well on even the deepest rooted
weeds (and no one else will mess with you when you’re using it). I stay away from
the use of chemicals.
Avoid seed set on the weeds as much as possible. One year I had a fantastic
specimen, a 6-ft. bull thistle (Cirsium vulgare) flowering in my garden that made
quite a show at an open garden tour. Visitors looked at it questioningly, afraid to
ask whether it was another unusual plant of some sort, although it looked
strikingly familiar. Could it be a type of Acanthus, or Cynara? I deadheaded the
early flowers before seed set so that I could enjoy the flowers (and this little
game) before removing the entire weed plant from the garden. Not something I
would recommend on a regular basis, but look at the choices pruning provides!
RENOVATION OF THE ESTABLISHED
PERENNIAL GARDEN
Frequently I am called upon to help with an existing perennial garden; the call
can come for a variety of reasons. The owners may have decided that they are
tired of the existing planting. They may have planted the garden themselves,
with little background knowledge, and it never quite measured up to their
expectations, or the planting might have been pleasing at one time but is now
overrun by aggressive weeds. Often the plant performance was less than
optimal, either because of poor plant choices for the growing conditions, or
more often than not, poor initial soil preparation. Usually the owners are
attached to some of the plants in the garden but could do without others, opting
for newer introductions with longer bloom times, more fragrance, or perhaps
finer habits. They have moved and removed things, added and subtracted, but it
still doesn’t gel. What to do?
In such cases we opt to renovate the garden. You start with some of the existing
plants, design in some new plants, and most important, amend the bed properly.
It’s a fun and at times daunting process, but one that is always worth the effort in
the end.
The first step is to evaluate the site. How much sun does it really get? Have trees or
shrubs matured in such a way that the sun patterns or moisture levels of the garden
have changed since it was first planted? Has new construction changed any views?
I believe in planting a garden
densely, in many layers, not only
for season-long interest but also
to help keep weeds down. It’s
actually best if you have to
shoehorn in new plants.