Oregon grape

Friends or Enemies? No, Just Plants.

“Peach-Leaf Bellflower, Garden Enemy #2” is one of my most-viewed posts. It was written in a fit of pique after I stabbed a hyacinth bulb while engaged in a heavy session of digging up peach-leaved bellflower (Campanula persicifolia) that had spread by runnng roots. I have since relented in my harsh judgement of that plant.

Partly it’s because I’ve decided there are plants even more apt to spread and harder to control. To wit: Oregon grape, snowberry, periwinkle (both Vinca major and V. minor), achillea, bloody cranesbill (Geranium sanguineum), and certain daylilies. I’ve fought more desperate battles with these than I ever waged against the bellflower (which is rather attractive just now, in its first flush of bloom).

It’s dumb of gardeners to blame plants for being themselves, bestowing upon them unkind epithets such as “thug” or “garden enemy.” (Not that the plants give a damn). I’m the one who decided to plant peach-leaved bellflower, Oregon grape, and snowberry in my garden, thinking them good choices because they are drought-tolerant, or native species, or both. Thing is, they succeed in our local conditions precisely because of their deep-rooting, runner-producing tendencies.

A recent reading of Noel Kingsbury’s excellent book, Garden Flora, gave me a new perspective on this — grouping or classifying plants by ecological habit, as well as by habitat or anatomy.

In looking at the longevity and persistence of plants, some are called “clonal” and others “non-clonal.” The first group includes those that spread by rhizomes, roots or stolons, and others that stay in one place but increase in size. Non-clonal plants are generally short-lived, but produce lots of seeds to ensure persistence. Both types are represented in my garden. The spreaders and seeders are the ones that give me grief, and on the whole, the seeders are easier to deal with. Deadheading is a lot easier than digging up Mahonia roots, let me tell you.

Kingsbury says the non-clonal plants tend to be pioneers, moving into an area and flourishing briefly, only to be supplanted by clonal competitors, whose roots, whether running or expanding in place, allow them to dominate their environment.

Learning about the science of things is a good antidote to the human tendency to personify. Plants don’t run or produce zillions of seeds just to bug gardeners, but as a survival technique. If gardeners were aware of these habits before they introduced plants to their precious patches of earth, much physical exertion and gnashing of teeth could be avoided, or at least minimized.

It would be helpful if writers of advice for gardeners included this aspect of plant performance in their writings. I’m sure if I had read something like “this is a tough, drought-resisting native plant, but gardeners should be aware that it spreads vigorously in conditions that meet its needs,” I would have avoided some plants, and situated others more carefully.

Beguiled by fervid descriptions of a plant’s flower colour, reliability, or the fact that it’s a native adapted to local conditions, I have rushed out, bought one or more, and installed them in my small patch of land. They took hold and flourished. Fast-forward a few years to see me whine and swear at colonizing shoots metres away from the original plant, often in the middle of some pampered darling that’s trying to make up its mind as to whether life is worth living. By this time, of course, the original plant has grown large enough that removing it would be a major project of the back-breaking variety.

The gardener mutters and swears. The clonal plant clones. The planet rotates. The gardener digs, chops, mutters, and swears.

Innocents, take note!

June 11, 2016

The Hori-hori Knife — essential weapon for battling suckers.

So Long, Sucker! But There’s (Another) One Born Every Minute.

My garden is full of them. Suckering shrubs — Oregon Grape (Mahonia aquifolium), Snowberry (Symphoricarpus albus), and common Lilac (Syringa vulgaris) — the last now in glorious bloom. There’s a suckering tree as well — the dreaded Tree of Heaven (Ailanthus altissima), known around here as the Tree from Hell.

Common lilac in bloom

Common lilac in bloom

The standard advice for dealing with suckers is to trace each one back to its point of origin on the parent shrub and tear, not cut it off. Tearing has a lasting effect, apparently (similar to plucking rather than shaving unwanted hair). Remove soil if necessary to accomplish this, the advice says, helpfully. Well, that’s fine if the shrub and its suckers live in solitary splendour with nothing around them except grass, possibly, but what do you do when the shrub is surrounded by perennials, bulbs, groundcovers, and even other shrubs? “Removing soil,” otherwise known as digging, isn’t really an option in a densely-planted mixed border, especially if a multitude of suckers has popped up several feet away from the parent plant.

The best advice is don’t plant sucker-prone shrubs to start with, no matter what other qualities they possess. So what if they’re native plants? Both Mahonia aquifolium and Symphoricarpus albus are native to my region, adapted to local conditions and trouble-free. They settled in happily here, sending up shoots with enthusiasm over the years. If I had several acres at my disposal and wanted a natural garden that could be left to its own devices, these plants would be great, but on a 50 x 120 foot lot (that also accommodates a house, garage, driveway and paved walks), planting these and other suckering shrubs guarantees either a wilderness effect or a gardener ready to nuke everything with herbicides and start over again. (I wish I could go back in time and give my younger self this lecture).

So — with the “nuclear” option not practicable, and not being ready to move to another patch of land, what do I do about suckers (besides curse and wail)?

In theory, it would be good to create a cordon sanitaire around sucker-prone shrubs, clearly defining a no-go area for each one. No suckers beyond this point! This would be done with a sharp spade, plunged into the ground all around the offending shrubs, at a distance of several feet. The process would have to be repeated at least twice a year, similar to edging a bed or border. Given the brutality and intensity of the work, there could be no plants of value growing in this foot-wide space. But setting a border makes the situation seem less chaotic and limits the space in which sucker removal is absolutely necessary.

Any suckers detected outside the cordon sanitaire would (in theory, at least) be removed immediately using minimally invasive techniques. First, the good old yank-by-hand method. Sometimes it works. More often than not, the sucker snaps at ground level, leaving a stump that’s hard to hold on to. Or the bark strips off, resulting in a little whip that’s too slippery to yank. A tool is then needed. For small young suckers, a dandelion tool works. Thrust it parallel to the sucker until it cuts and the sucker releases. (But remember, cutting isn’t as effective as ripping). For older, thicker suckers, a small, cheap, pointed saw of a type designed to cut gyprock (sheetrock) works fairly well. Like the cutting-with-spade procedure, this search and destroy operation is best repeated at least twice a year. Three or four times is better, especially in regions with mild winters. Constant vigilance is best.

I have a fleeting hope that if I follow these processes diligently, the shrub will get the message, “None of your suckers will live to see the light of day!” and stop sending out the roots from which suckers grow. But somehow I doubt that will be the case.

A forest of Oregon Grape suckers

A forest of Oregon Grape suckers

In reality, the years have a way of slipping by, and the gardener is not as diligent as necessary. In my garden, it’s too late for the cordon sanitaire. Roots of Oregon grape and snowberry have spread far and wide. For the past several days I’ve been engaged in an epic struggle with an enormous Oregon Grape (Mahonia aquifolium). I removed three large stems (diameter 2-4 inches at the base) and reduced the remaining plant’s height from about 12 feet to 8. Worst of all was pulling, digging or cutting (sometimes all three) a multitude of suckers, ranging in size from less than a foot tall and 1/4 inch in diameter to 4 feet and 1 inch diameter.

Oregon Grape prunings (right) and suckers (distant left)

 

Typical Oregon Grape suckers

Typical Oregon Grape suckers

 

2

The "after" picture

The “after” picture: remaining Oregon Grape visible behind the Ceanothus

I cherish no illusions that the suckers are really gone. Their stubs and deeply buried roots are still there. They will no doubt rise again, like a bunch of prickly green zombies. Really, the best way to avoid suckers is not to plant suckering shrubs. And if any plant shows suckering tendencies, rip it out.

This lone orange tulip has been blooming for weeks -- and doesn't sucker!

This lone orange tulip has been blooming for weeks — and doesn’t sucker!