Review what worked and didn't as you plan next year's
garden
Our gardens take a rest in winter but our brains grow on.
Winter's the time to review what worked and what didn't, what to
expect back next year and what holes there will be to fill.
There is no statute of limitations on the review. Sooner is
best, while memories are clearer, but it's never too late to think
back. At worst, we laugh at ourselves and move on, avoiding any
repeat of that mistake. At best we pat ourselves on the backs and
do our best to recreate the glory.
For instance,
Poet gardener Frank Harney posed us a puzzle that's been bugging
him for years. Here's the situation, our reply
in summary and details in Essential shade.
Hi kids.....
The most thoroughly researched, meticulously measured,
designed, executed plan since the Pyramids.... and it
FAILED!!!
Roughly 12' x 20', full shade, thus the research, plants
chosen for their shade tolerance, hardiness, beauty, all to no
avail.
Its own sprinkler system, half inch black plastic with
punch-in nozzles, one for each plant, hah! That Norway maple
must've been a regular sponge. Couldn't keep enough water on the
area to keep it damp.
Three different types of ferns, bell flowers, bleeding
hearts and other varieties I no longer remember. ALL
GONE!!
Photo ©2012 Frank
Harney
I still have the bird bath, the red and buff blocks (now
a patio and part of my walk to the garage). I still had one
bleeding heart until I saw that my daughter had discarded the wire
cage and plastic ring that marked the spot after it had gone
dormant, and planted a lavender. I'll wait til spring to see which
one prevails. Oh yes, primulas, or primroses, whatever. Some
of
those made it. I gave away the last of them
last year when I was "cleaning up." - Frank
-
Right: We went and looked at Frank's garden, and added these
details to his photo.
We think you hit the biggest nail right on the head,
Frank -- Norway maples.
(Acer platanoides). They are vicious competitors on
three counts:
- First, they block all the light for a very long season
beginning at bloom time -- their yellow-green flowers are so
abundantly borne (but rarely recognized as flowers!) that the
branches cast dense shade even before the leaves emerge. The shade
continues thick until leaf fall, which comes later than most other
trees. Only oaks, callery pears and buckthorns outlast 'em.
- Next, they do indeed suck up water with a thoroughness and
insatiability almost beyond belief.
- Third, they're allelopaths, meaning they produce
growth-inhibiting chemicals that discourage many plant
species.
We'll summarize here, the report the nitty gritty on three other
pages, to help you see more angles for meeting this
challenge.
Some trees are more ruthless than others in what they take from
a bed. How much root tip they grow, and where, come into play.
The fine branches concentrated at the end of a root are the
tree's primary water collectors. Some trees' roots are especially
good at producing these tips.
Right: In this collection of various trees' and shrubs' root
ends we unearthed in a garden one day, note that one is much more
densely clad in absorbent root tips (far right, arrow). That's a
Norway maple root.
Over time, a tree's main roots become thick and woody and in
most species these older segments quit producing side branches
(tips) and no longer absorb much water through their own outer
surfaces. They simply transport what their far-end tips
collect.
Norway maple is an exception. So is another invasive Eurasian
species, the buckthorn (Rhamnus cathartica).
Below, left are root ends from a buckthorn. As is
right and proper in most woody species the biggest water users --
the fine, branched tips -- are concentrated at the end of the
root.
Below, right: Yet look at the buckthorn's whole root
system. All the soil's been washed off -- the dark center of the
ball is not soil. It's massed root tips. Like the Norway
maple, it's so efficient at using water that it readily develops
root tips even from its oldest, thickest roots near the
trunk.
Okay, enough detail where we meant to simply summarize!
The gist of our answers to
each Norway maple challenge:
- Prune and keep pruning a maple
to elevate and thin the crown. Plants need light or they have no
energy to establish quickly, and photosynthesize so slowly that
they can't draw up water even if it's available.
- Water slowly and copiously
every day. Let it run slowly and continuously, or water every
morning, all morning. No way can shady perennials compete with a
tree during peak hours in the afternoon, when water literally runs
up the tree, drawn by evaporation. Start watering early in spring
before the maples flower, spot watering emerging perennials. Do not
tolerate any weeds, not one. Even the tiny ones are killer
competitors for scarce moisture.
- Choose plants as best you
can. It sounds like you did well, honestly. There is no
scientifically sound list to help in this regard, telling what does
and doesn't grow well with Norway maples. (There are such lists for
black walnut (Juglans nigra), the head honcho of
allelopaths -- plants that are plant killers. Walnuts are
native in agricultural fields. Their relationship to crop plants is
important and well documented. Norway maples inhibit and kill
plants in landscapes, a situation that does not earn so many
research dollars.)
- Grow what you chose. Then cull the herd, propagate those that
thrive, trial more species and so on until you have 8 or 10
winners.
Last word of summary: Never expect a shade bed to look like a
sun garden. In the woods under maples there is less diversity than
in a garden. Only a half dozen species may be there, but each will
be thriving and covering large areas. Scattered about will be what
appear to be bare spaces, but these are actually fully occupied by
tree parts below or especially dense foliage above. That space is
already at carrying capacity, so fill those necessary voids as
below, with paths, stone, artsy fallen logs, a bigger bird bath,
etc.
