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Failures tell tales
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 -
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 went and looked at Frank's garden, and added these details to his photo.
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.
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).
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.
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.
