Field maple

Acer campestre is the only maple native to Britain. It grows in hedgerows and on the edges of woods across England and Wales, on chalk, clay and almost anything else, and it has been cut, laid and trimmed by farmers for a thousand years without complaint. That history is the whole case for it as a bonsai tree. It takes pruning the way a hedge takes a flail, it back-buds from old wood, it carries small, five-lobed leaves that reduce well, and it costs almost nothing: bare-root hedging whips are sold by the hundred every winter, and old, gnarled trunks come out of hedges that are being grubbed up.

It suits a temperate garden better than many imported species, for the simple reason that it is adapted to changeable weather. It does not scorch in sun, it does not mind wind, it shrugs off a wet winter and a dry summer, and it is very hardy. The leaves are a soft matt green, smaller than a Japanese maple's and rounder in outline, and in autumn they turn a clear butter-yellow, sometimes with orange, that is one of the quiet pleasures of an English October. The bark on an old trunk is corky and fissured, and the twigs of a mature tree often carry corky wings, which give a bonsai a convincing age.

Beginners go wrong with it mostly by expecting too little. Because it is cheap and tough it gets the worst spot on the bench, the leftover soil and the least attention, and it responds by growing coarsely: long internodes, big leaves, a crown of thick shoots. Treated like a Japanese maple, with the same pinching, cutting back and attention to water, it becomes a refined tree. The other mistake is the opposite: being too timid with a collected trunk. A field maple from a hedge can be cut back to a stump and will bud from the bark; the first year's job is to let it grow freely and build root, not to make a bonsai of it.

Through the year it lives outside, in full sun or light shade, in any sheltered spot. In winter it stays out and bare, with the pot on the ground or in a cold frame only in a spell of hard frost with wind. It does not need a greenhouse and is better without one. It is one of the few species where the beginner's instinct to leave it alone over winter is correct.

The growth habit is that of all maples: a spring flush from late March, shoots extending until early summer, a second small flush in a good year. It is apically dominant but less violently so than a trident, and it back-buds on old wood after pruning, which makes it easy to develop a crown of fine twigs from a heavy branch. Pinching the opening shoots, cutting back to one or two pairs of leaves in June, and partial defoliation on a strong tree all work. Cuts heal cleanly and large wounds close in a few seasons.

It wires well: the bark is tougher than a Japanese maple's and marks less, so wire can stay on longer, though it still needs checking monthly in the growing season. Branches set in a season. Collected hedgerow trees often have a trunk with character and no branches worth keeping; those are built from scratch by clip-and-grow and wire over three or four years, which is the best apprenticeship in deciduous bonsai that money cannot buy.

Seasonally it gives a bright green spring, a modest summer, a yellow October and a winter silhouette that, on a well-worked tree, has the density of an old hedge. It will never have the elegance of Acer palmatum and does not need to. A field maple grown from a whip in a tray, or from a stump out of a hedge, is the most honest bonsai a grower can make, and the one most likely to outlive its owner.

• Informal upright (moyogi): a hedgerow tree's natural shape: a trunk with movement, a broad crown of fine twigs
• Broom (hokidachi): the fine, dense twigging of a hedge-cut field maple is exactly what a broom needs
• Slanting (shakan): a leaning hedgerow trunk, collected or grown on, reads naturally in a pot
• Forest group (yose-ue): bare-root hedging whips are a few pence each and make a convincing English grove in a tray
• Windswept (fukinagashi): field maples on exposed downland grow leaning away from the wind, and a tree can be shaped to say so
• Root over rock (sekijoju): the roots are less fleshy than a trident's but still grip a stone well over a few seasons

2 parts akadama, 1 part pumice, 1 part lava (by volume); it also does well in a cheaper mix of 1 part akadama to 1 part horticultural grit for a tree in training

A native of chalk and clay alike, the field maple is not fussy; what it wants in a pot is drainage through the wet months and enough water-holding to get through a dry June.

Glazed, as for any deciduous tree, in an oval or a soft rectangle about two thirds the height of the tree in length and about as deep as the base of the trunk. The leaves are small and matt and the tree is rustic, so a muted glaze suits it: a soft green, an oatmeal, a grey-blue or an unglazed-looking matt brown glaze. Bright glazes make it look like a garden-centre plant.

A forest of whips goes in a shallow tray or on a slab. A heavy collected trunk in training belongs in a wooden box or a big plastic pot until the branches are built; a bonsai pot on an unfinished tree slows everything down.

Aphids on the spring shoots, sometimes heavily, which curl the leaves if they get ahead; squash them early or use a soft-soap spray. Vine weevil grubs in any pot; nematodes in late summer and spring. Gall mites make small red pimples on the leaves of hedgerow trees and sometimes follow a collected tree into the pot; they are harmless and the leaves are removed if they offend.

Powdery mildew, a white dusting on the leaves in a warm, dry late summer, is the one common disease; it is cosmetic, worse on a tree in still air, and goes with the leaves in autumn. Good air movement and a bench rather than a corner prevent it.

What every month's line rests on: RHS H6: a native tree, hardy in the ground; a shallow pot still wants shelter from a hard frost, because frozen roots cannot replace what a drying wind takes from the twigs.