hostas

Rooting

A couple of weeks ago, I engaged in yet another epic struggle with tree roots.

A perennial bed that was root-free when first planted (about twelve years ago) had been showing signs of decline for several years. Plants were smaller and obviously struggling, especially the hostas. Turns out hostas don’t compete well in rooty situations; strange, considering at least some species are native to woodlands. Not woodlands of Norway maples, I suppose.

I’m pretty philosophical about the older beds in the back garden. After all, they are close to five large trees, three of them maples (1 red, 2 Norway), whose roots interlace in a network throughout that 50 by 50 foot space. Goodbye, vegetable patch. Tough plants only. But this newer bed, situated in a narrow strip of land between my house and my neighbours’, was, I thought, far enough from any tree to remain root-free. The drip-line (canopy edge) of the closest maple was safely distant, and tree roots don’t extend beyond the drip-line. Or do they?

Yes, they do. Roots roam far and wide, as it turns out. Once I discovered creeping rootiness in that new bed, I started reading up on how tree roots grow. There was surprisingly little written for home gardeners, even those who are familiar with Latin plant names. I found a lot of scientific papers written by researchers in the fields of forestry or agriculture. Their focus was narrow and their terminology over my head.

Finally, I found this — relatively comprehensible and relevant to my situation. Also discouraging. The drip-line idea is one of the fallacies. Au contraire, “it is not uncommon to find trees with root systems having an area with a diameter one, two or more times the height of the tree.”

tree-309046__340

This isn’t how it works! (Image from Pixabay)

Trees send out long, questing roots that keep on growing as long as there’s a reward in the form of water or nutrients, as in a fed and watered perennial bed. The roots run along horizontally, sending up vertical subsidiary roots ending in fine mats of feeding roots. Those are the ones that make that typical ripping sound when a spade is thrust into the soil.

So I tried a strategic strike. I dug up a clump of purple monkshoods (Aconitum napellus) and a few young hellebores at the end of the bed closest to the tree I suspected to be responsible for the root. Then I excavated down two feet and indeed found not one, not two, but three roots a couple of inches apart, each of them about two inches in diameter. Using a nifty little saw (actually intended for cutting wallboard) and a hatchet, I removed sections of these roots, one to three feet in length. Then I dumped in some compost and replanted the aconites and other plants. Thanks to cool and rainy weather, they recovered nicely.
I hope this will give the perennials in the beleaguered bed a chance, if only for a season or two. I don’t relish the thought of a full-bore rebuilding of the entire bed in the grand manner. This rather limited effort was enough for an aging gardener.
October 20, 2011

Hostas, autumn of 2012.

Remaking a Perennial Border

I suspect most naive gardeners (even those with years of experience) think that a perennial bed or border, once made, is a done deal. Plants may come and go, but taking the whole thing apart and reconstituting it is unthinkable — sort of like rebuilding a house. But of course a perennial border is a collection of living things, so it’s bound to change. Over time, the tough and hardy plants muscle out the weak and fussy. Some inevitably become dominant in the picture, while others disappear.

Consider these two views of my back garden:

Back Garden, Fall 2010

Back Garden, Fall 2010

 

Back Garden, September 2015

Back Garden, September 2015

 

The same scene, obviously, but details are different. Some plants have grown bigger or more numerous, while others have declined or disappeared. Superficially, though, one could say it still looks fine, despite the addition of dog-excluding fences in the 2015 scene. But I know it was lusher, fuller and better-maintained five years ago.

I plan to retire from my job next spring. Near the top of my list of post-retirement projects is an overhaul of the garden, yanking it out of its present state of decline. Over the years I have whined about the effect of tree roots on perennial beds and vegetable patch (now the Ex-Veg Patch). I have vacillated between accepting the inevitable (substandard beds and borders in dry, rooty shade) or doing the heroic (and expensive) — tree removal.

Now I wonder if there is a third option — rebuilding the border. I remember reading a description of how English perennial borders (the ne plus ultra of this form of gardening) were taken apart, re-dug, enriched and replanted every few years. This was (still is?) a routine procedure, intended to keep the border at a peak of perfection.

Something like that — which I admit sounds pretty heroic, if less expensive — may be the answer, especially as I’ll have more time but less cash.

So, a plan is needed. What plants to dig up and return to refreshed, de-rooted soil. What plants to dig up and discard. What plants to leave in place because they are too difficult to dig up. And I have to decide just when all this digging is to take place. The usual seasons for planting and dividing perennials are spring and fall. A rough rule is to divide spring bloomers in fall, and summer and fall bloomers in spring. But I think this operation is best done in spring, or even earlier — mid-February to mid-March, which I think of as “pre-spring” here on the fortunate west coast. With some care I’ll be able to extract the plants to be kept with enough soil around the roots that they won’t even know what’s happened.

As for the final configuration of the beds, I’m considering fewer large and medium plants and more low groundcovers, such as variegated periwinkles, which are not as pushy and vigorous as the plain types. I’d like more hostas, but I’ve come to realize they really don’t do well in rooty soil. The only way I can grow them well is in pots. Therefore, a combination of large ferns (Dryopteris species) snuggled up to potted hostas (the ferns concealing the pots), with some white foxgloves in the background, and the stalwart hellebores, of course… Too many large plants already? Well, I’ll work it out.

The best gardens, of course, are those in the gardener’s imagination.

In the meantime, it’s reassuring that this small area near the pond, right now, looks a lot like this picture, also taken in 2010.

Hosta (in pot), with Hellebore and Cyclamen, Fall 2010

Hosta (in pot), with Hellebore and Cyclamen, Fall 2010