In the garden, cleanliness is not necessarily next to
I'm continuing to work through an unusually high volume
of mail. I've condensed my advice on the hottest topics to cover as
many of your concerns as I can.
Do I have to take the mulch off my beds?
No. At most of the U.S. public gardens I've polled, mulch is
left on the beds year round. It's topped up whenever the gardener
notices that it's decomposed to less than about an inch deep. Fall
is high season for mulch renewal. It may be applied deeper then,
since it will partially decompose and settle by spring.
It's an English convention to remove mulch from a bed in spring.
The tradition might date back to the Roman occupation and the fact
that far-north latitudes receive lower angle, weaker sun than
Mediterranean climes. Bare soil, darker than most mulches, absorbs
more heat and warms up more quickly than covered soil. Thus
vegetable-planting can happen sooner. In the U.S. Midwest, we
receive stronger sun than England does. Our soil temperatures jump
rapidly in spring, no gardener-assist necessary.
I was told a healthy garden is a clean garden, so I rake
everything out in spring.
The advice to keep a bed cleaner to keep it healthier is right
on if you have experienced serious disease problems with specific
plants, or are growing plants you know are disposed to certain
life-threatening diseases. It can pay to remove all the debris that
falls from such plants, not every plant, removing the affected
material not just once a year but on a regular basis and disposing
of it in a hot compost pile. This reduces the sources of infection.
However, in an otherwise healthy garden, that protection's not
needed. Plants and soil can benefit more from continual
replenishment of organic matter through decomposing plant
Although fallen debris can harbor trouble-maker insects and
diseases, it is also home to beneficial insects, helpful fungi and
bacteria -- organisms which far outnumber their pesty counterparts.
Leaving healthy debris in place helps maintain a balanced garden
ecosystem. Pests will be preyed upon by their natural enemies and
we will have less work to do since we won't have to get involved in
Can I make the soil in my perennial garden better
without digging out all the plants that are already
Certainly! Each year, add two or three extra inches of compost
or organic matter between plants, keep it moist and let Mother
Nature's tillers go to work for you. This technique doesn't pay off
as quickly as removing the perennials or bulbs and then digging to
loosen the soil, but it works!
If you add an extra-deep layer of compost or shredded leaves
while the ground is still cold, you can cover right over
perennials, which will usually emerge without trouble. My
soil-improvement routine is to top-dress beds with compost in fall,
since the window of cold-weather opportunity is larger in fall than
in spring. This spring, the window may be especially small, since
late springs come on fast and progress very rapidly.
You can also improve the soil with plants in place by drilling
holes throughout the area and filling them with compost. In
relatively loose soil, a bulb auger does the trick but where the
soil is very heavy and packed down, I rent a power post hole
Call Miss Dig before you drill (800-482-7171) so that major
utilities can be marked before you start drilling. Keep in mind
that utility companies can only locate your primary connections to
electric, gas, phone and cable TV, not all the secondary
connections and other items that may be buried on your property.
Locate sprinkler lines first, if you have a buried irrigation
system, avoid invisible dog fences, and avoid the power or gas
lines to outdoor security lights.
Can I add soil over tree roots to make a
Yes. You can make a new garden or improve an old one by raising
a bed under a tree. Don't use soil, though. Use compost. This
mimics natural soil-building in a forest, where thick layers of
fallen leaves decompose and build new topsoil every year.
Always keep the trunks of woody plants clear of whatever you use
to raise the grade, however. If you walk in the woods you'll see
how normal leaf fall and wind patterns keep debris from
accumulating directly against tree trunks. Mulch and other organic
matter stacked against a trunk can kill even a large tree through
Green thumbs up
to steady cold, for bulbs' sake. Bulb plants may be better off
this year than when winter warm-ups cause their foliage to emerge
early. Although precocity doesn't kill the bulb it can freeze leaf
tips, making them less attractive, more susceptible to leaf spot
fungus, and less energizing to the flower.
Green thumbs down
to breaking the icicles off shrubs. Certainly you're anxious to
remove the last bits of winter but you damage the wood when you
beat and snap off ice. Support the frozen limbs with props instead,
and let everything melt gradually while you look at ways you can
prevent that freezing drip next year.
Originally published 3/15/03