As most of you know, my gardening education has been a little unorthodox. I attended the trial-and-error school of horticulture. I still follow my gut instead of the rule book, and (sometimes) learn from my mistakes.
So audacious am I that in 1990 I launched a quarterly publication called The Garden Letter, as if anything other than a background in journalism qualified me for educating novice gardeners.
I myself was a novice gardener.
In many ways I still am. I still have to consult Google for Latin names. In conversation I disguise the fact that I have no idea how to pronounce the ones I do know.
My work-around is the common name. Not only is “burning bush” English, but it’s descriptive and easier to recall than Euonymous alatus.
Likewise, “purple coneflower” easily comes to my mind when I’m asked to identify Echinacea purpureum, on account of the way the petals slope fetchingly downward, resembling a badminton birdie.
Unfortunately, coneflowers now come in all colors, not just purple, and most of the new cultivars have also lost those charming sloping petals, for reasons I can’t fathom.
The trial-and-error method is not, of course, for everyone. But I will say, in my defense, that new research on memory suggests that hands-on learning is more effective than the other kind — it sticks in the brain better.
A classic example of my seat-of-the-pants method involves a Japanese larch (Larix kaempferi) that I planted five years ago.
The larch genus is also called tamarack. My learning curve with this plant was anything but bell-shaped. Picture instead a mountain range, lots of jagged peaks and valleys.
I bought the larch on impulse, beguiled by what I thought was a dwarf shrub of some sort, so charming in its 10-gallon pot.
It is now a robust tree measuring 8 feet tall and 12 feet wide. In a few years it may soar to 20 feet, possibly even 40 if I let it.
I don’t intend to.
Technically, the species is not hardy here. “Here” is still considered USDA Zone 4, though for years garden centers have been taking advantage of warming temperatures to sell exotic new species — exotic in these parts, anyway.
Japanese larch is one of those. It is rated hardy to Zone 5, meaning it can withstand low temperatures at a maximum of 25 degrees below zero.
You may recall last winter’s sudden January cold snap, following a long and lovely autumn. It damaged a number of my plants. Yours, too. My email correspondents reported heavy losses.
Among the victims in my garden were two Japanese maples (Acer altropurpureum “Crimson Queen”) and a contorted black locust called “Twisty Baby.” Both species are hardy to Zone 5.
But it wasn’t the cold that almost killed them (each lost a third of its canopy). What got them was bad timing.
Both species evolved in places where fall lingers and the transition to winter is gradual, not abrupt. This gives them plenty of time to shut down the systems that cause active growing and hunker down for the winter with their leaf buds fully insulated by a thick outer shell.
If the culprit wasn’t the early cold, then it was a late freeze. Remember, we also had a miserable (some would say nonexistent) spring.
Same difference. Bad timing.
I pruned the dead branches and stacked them in the kitchen beside the wood-burning stove.
Then I went back outside to inspect the damage I’d done. Were they now too ugly to be worth saving?
The Japanese maples had been trained to grow horizontally. The removal of their long drooping limbs was severely disfiguring. Imagine if Rapunzel were given a bowl cut.
Pruning didn’t much change Twisty Baby’s columnar appearance. It’s just a lot shorter.
There was one good thing about last winter. The Japanese beetles were decimated by the cold.
Which returns me to today’s topic: tamarack, also known as larch.
While I am grateful that my Zone 5 Japanese larch emerged from last winter relatively unscathed, it seems there’s another threat looming. Our frigid winters used to kill off the larvae of deadly pests. Japanese beetles are only the most notorious with gardeners, followed by emerald ash borers.
Now tamarack beetles are on a tear.
My first (shamefully selfish) thought when I read the news stories was … what about MY tamarack? Is it at risk?
The short answer is … maybe.
Emerald ash borers kill ash trees, no matter the species. So also, I presume, do larch beetles kill all types of larch. If my larch were growing in its country of origin, Japan, it would be protected by the beetles’ natural predators, which don’t exist in places where the beetle itself did not evolve.
I see no reason why the insect won’t enjoy munching on L. kaempferi as much as it does the native L. laricini, unless our northern tamarack is more appetizing because of some other trait — for example, its preference for boggy conditions.
But my guess is that whether we’re talking zebra mussels or buckthorn or Japanese beetles or emerald ash borers or tamarack beetles or (the worst of the worst) stinkbugs, exotic species don’t care where their victims evolved. To them a rose is a rose is a rose.
So also, a larch is a larch is a larch.
Adding to the troubles of forestry managers is this:
Larch used to be popular in the trades; its straight trunk made a perfect telephone pole.
Pine poles took over because of the difficulty of removing trees in boggy conditions made even boggier in winter because the ground no longer freezes. Modern machinery isn’t as flexible as a lumberjack.
Lacking a market, the trees will stay put, giving safe harbor to the enemy — whose Latin name, by the way, is Dendroctonus simplex.
Arborists also blame our warming climate for the drought that encouraged beetles to feast on weak trees.
But enough bad news. What intrigues me is why, despite its unique status as a “coniferous deciduous,” tamarack never caught on with landscape architects here in Minnesota as other marginally hardy newcomers did.
Why wasn’t there a boom in sales of the native’s more refined Japanese cousin, whose soft blue-green needles grow in fan-shaped clusters resembling (in shape) the single leaf of a ginkgo tree?
Japanese larch is a fixture in public gardens in Japan, and there are several in Como Park’s Japanese garden.
The weeping version (L. kaempferi “Pendula”) is especially alluring. It was my inspiration when I pruned off the main trunk (“central leader,” in proper hort speak) of my Japanese larch in an effort to force it to weep or, failing that, to grow sideways instead of straight up.
Yup, when the maples and the locust got their haircuts, L. kaempferi got one too, even though it didn’t seem fazed in the least by winter’s extremes. Remember those telephone poles?
I had no choice but to amputate.
A bonzai artist would never do this.
I vowed that henceforth I will treat my larch like a bonzai because, as it turns out, L. kaempferi is ideal for this purpose and a favorite with Japanese bonzai artists.
Live and learn, right?
If you’re a gardener, the opportunities never end.