The garden under the maple

A hundred-year-old bigleaf maple, a lawn that had not worked under it for a decade, and owners who wanted to stop fighting the tree.

The lawn was the problem and the tree was not. Acer macrophyllum is a surface-rooting species and it had won — the grass was thin, the soil was dry by June under a canopy that sheds very little rain through, and every attempt to improve it involved cultivating the root plate of a protected tree.

So we stopped. We removed the turf by hand rather than by machine, brought in no more than three inches of compost over the root zone so as not to smother it, and planted small — one-gallon stock and bare-root ferns, because small plants establish under root competition and large ones sulk and die.

The client found the first two years difficult, and said so. It looked sparse, it was sparse, and we had told them it would be. In year three the fern layer closed. In year six they stopped being able to see the fence.

Across 9 years

Every frame is labelled. The build photographs are in here too, because the fortnight where a garden is a trench is part of what you are buying.

Coarse fresh bark chippings filling the frame, pale tan and dry on top, with fragments of split wood and a few dead leaves caught in the surface. — Year one, MayForty per cent of a new bed looks like this. That is correct spacing, not a shortage of plants.

Young fern fronds rising from thick green moss on a fallen log, several still tightly coiled at the tip and others half opened, against a dark blurred forest background. — Year three, AprilNew fronds in April. Sword fern makes a year's growth in about six weeks and then stops.

A narrow stone path almost swallowed by planting — ferns arching in from both sides at knee height and tall white umbels of flower leaning over the stone, in soft green light with no direct sun. — Year five, JuneThe fern layer has closed over the mulch, but you can still read the path edge and the individual plants.

A close view of an old stone path where thick green moss has filled every joint between the setts and crept over the edges of the stones, with fallen leaves and low green planting at the margins. — Year nine, MarchWe did not put the moss there. It arrives on its own once the canopy closes, somewhere around year six.

Planting plan1" = 8'

Key — drawn at mature spread

POM×3Polystichum munitum — western sword fern
BLS×2Struthiopteris spicant — deer fern
ASC×2Asarum caudatum — western wild ginger
TEG×2Tellima grandiflora — fringecup
MAN×2Berberis nervosa — Cascade Oregon grape
GAS×2Gaultheria shallon — salal
HEH×1Helleborus × hybridus — Lenten rose
ACC×1Acer circinatum — vine maple

Solid outlines are evergreen. Dashed outlines lose their leaves — which is what a plan should tell you before you build it, not after your first winter.

The ground, and the water

Missoula Flood silt with a decent structure, but bone dry under the canopy from mid-June. Three inches of compost, laid on rather than dug in, and a further inch every spring since.

Drip irrigation on a separate zone from the rest of the garden, run deep and infrequently. It has been reduced twice as the planting matured and now runs eight times a summer.

What we would do differently

We planted the wild ginger too far apart. We were being careful about the tree roots and we spaced it at eighteen inches, and it took five years to knit rather than three. At twelve inches it would have cost another four hundred dollars and closed two years sooner.

The backbone of the planting

POMPolystichum munitumwestern sword fern3.5 × 4 ft at maturity
BLSStruthiopteris spicantdeer fern2 × 2.5 ft at maturity
ASCAsarum caudatumwestern wild ginger0.6 × 4 ft at maturity
TEGTellima grandiflorafringecup2.5 × 1.5 ft at maturity
MANBerberis nervosaCascade Oregon grape2.5 × 3 ft at maturity
GASGaultheria shallonsalal4 × 6 ft at maturity
HEHHelleborus × hybridusLenten rose2 × 2.5 ft at maturity
ACCAcer circinatumvine maple18 × 16 ft at maturity

Yours would be drawn the same way.

A measured base plan, a planting plan at mature spread, and a written note on what the garden will look like in year one so that nothing about the first winter is a surprise.

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