Rain Gardens – A how-to manual for homeowners
17
Maintaining the rain garden
Weeding will be needed the first couple of years. Remove by
hand only those plants you are certain are weeds. Try to get out
all the roots of the weedy plants. Weeds may not be a problem in
the second season, depending on the variety and tenacity of
weeds present. In the third year and beyond, the native grasses,
sedges, rushes, and wildflowers will begin to mature and will
out-compete the weeds. Weeding isolated patches might still be
needed on occasion.
After each growing season, the stems and seedheads can be left
for winter interest, wildlife cover and bird food. Once spring
arrives and new growth is 4-6-inches tall, cut all tattered plants
back. If the growth is really thick, hand-cut the largest plants and
then use a string trimmer to mow the planting back to a height of
six to eight inches. Dead plant material can also be removed with
a string trimmer or weed whacker (scythe) and composted or dis-
posed of as appropriate.
The best way to knock back weeds and stimulate native plant
growth is to burn off the dead plant material in the rain garden.
However, burning is banned in most municipalities. Another
option is to mow the dead plant material. If the mowing deck of
your lawn mower can be raised to a height of six inches or so, go
ahead and simply mow your rain garden. Then, rake up and
compost or properly dispose of the dead plant material.
If the mower deck won’t raise that high, use a string trimmer or
weed-eater to cut the stems at a height of 6-8 inches. On thicker
stems, such as cup plant, goldenrods and some asters, a string
trimmer may not be strong enough. For these, use hand clippers
or pruning shears to cut the individual stems.
What does a rain
garden cost?
The cost of a rain garden will vary
depending on who does the work
and where the plants come from. If
you grow your own plants or bor-
row plants from neighbors there
can be very little or no cost at all.
If you do all the work but use pur-
chased prairie plants, a rain garden
will cost approximately $3 to $5
per square foot. If a landscaper
does everything, it will cost approx-
imately $10 to $12 per square
foot.
It might seem easiest to sow
native wildflower seed over the
garden, but experience shows that
seeding a rain garden has its prob-
lems. Protecting the seeds from
wind, flooding, weeds, and garden
pests is very difficult, and the rain
garden will be mostly weeds for
the first two years. Growing plugs
from seed indoors or dividing a
friend’s plants is much better. If
you grow plugs, start them about
four months before moving them
to the rain garden. When the roots
have filled the pot and the plants
are healthy, they may be planted in
the rain garden