To benefit gardens, fertilizer must be moist and
covered or dissolved in water
Our perennial garden currently has 3 inches of mulch
covering it. Do we have to move the mulch away from each plant to
fertilize and then re-cover the area or can we simply put
slow-release on top of the mulch and ensure that it gets watered
into the area? Our garden is quite large and seems like it would be
an impossible task if we had to move the mulch away from each
individual plant to fertilize.
Also, can 'whole' fall leaves be left on the garden in
the winter or do they have to be removed, mulched or shredded and
then placed back in to the garden?
If it's woody mulch and granular fertilizer then, yes, you would
have to move the mulch aside or at the very lest scratch the
fertilizer into the mulch so it won't just lay on top. The granules
have to be in contact with moist soil or mulch for some time in
order to melt and become useful to plants. Sitting high and dry on
top, they do little if anything.
If it's a woody mulch that persists more than one season, use a
water soluble fertilizer during the growing season -- fish
emulsion, compost tea, manure tea or one of the blue powders you
dissolve in water.
The mulches I like best for perennials are leaves, grass clips,
cocoa hulls or finely-ground bark. These break down within the year
after they are applied. I add slow release fertilizer to those beds
right before I renew the mulch each fall, when the old mulch is
thin-to-gone. I use these kind of mulches not just because they
make fertilizing easier but because they renew the soil better,
something a perennial bed needs.
You can leave the leaves as a mulch or an addition to a mulch. I
use leaves pretty much exclusively on my own gardens in fall, whole
or shredded. A layer that is four or more inches deep in fall will
be just about broken down by late spring. However, sitting on top
of dry woody mulch they may not break down well over winter or at
the beginning of the next season. For this, too, moisture is
I have read that mulching in the Fall is a good thing
but that it should be done in the late fall or early winter after
the ground freezes.
Sometimes the ground doesn't really freeze until very
late (after New Year's) if at all, right?
We (me, and 26 managers of public gardens I've interviewed on
the topic) mulch all year, whenever we need to top up a mulch. I
throw leaves all over my gardens any time beginning now, when
Nature begins to do just that, and have had no problems.
What you have read confuses advice about normal mulching with
adding a heavy mulch to protect marginally hardy plants over
winter. Such extra-deep mulch should not be applied over a plant's
crown until we're pretty sure both the plant and burrowing animals
are dormant, so the plant won't rot and the critters won't find an
inviting pile to use for a winter den.
Some fast-growing trees to replace ash.
L.M. writes to ask which fast-growing trees she might plant to
replace a back-yard ash tree that was removed after becoming
infested with emerald ash borer.
These trees would fit the bill: Redbud (Cercis
canadensis), serviceberry (Amelanchier species),
golden rain tree (Koelreuteria paniculata), katsura
(Cercidiphyllum japonicum), hackberry (Celtis occidentalis), bald
cypress (Taxodium distichum), dawn redwood
(Metasequoia glyptostroboides), and lacebark elm
(Ulmus parvifolia). Each can be expected to grow one to
two feet per year or more.
Those and other trees, with descriptions and sources, are on a
list you can have by sending me a long, self-addressed, stamped
envelope and one loose first-class stamp to cover my copy costs.
The list is also posted on www.michigangardening.com.
River birch (Betula nigra) is another tree that might
be just right for you. (It is not on the list, but only because a
list has to stop somewhere.) It's a 40 to 70-foot shade tree that
is mistakenly planted as an "small" ornamental by people who do not
know its potential. It grows 1 to 2 feet per year and although the
flower is not showy and the yellow fall color is not outstanding,
the cream- and cinnamon-colored peeling bark on younger trees is
attractive. The bark becomes thick and gray-brown on older limbs
and the trunk. Grow it in full sun in moist, well drained soil
Green thumbs up
to cutting it down as it becomes brown. Rather than doing all of
your perennial garden clean up at once, cut back each plant to the
ground as it begins to detract from the overall look. This way a
big job becomes just a few short forays into the garden, and
fall-bloomers like aster and toad lily look better since any
eyesore companions are gone.
Green thumbs down
to buying dried-out bulbs, no matter how inexpensive. Bulbs
stored too long, too dry feel soft rather than firm. They may grow
weakly then not bloom or may die and in dying load your bed with
pathogens to infect other bulbs.
Originally published 10/2/04