Hornbeam

Light and exposure

Hornbeam copes with any exposure, from full sun to fairly dense shade under large trees. That is one of its great advantages over beech: where beech starts to sulk in shady woodland, hornbeam keeps growing without complaint, which makes it the natural choice for a hedge along a wall that never sees the sun or under the shadow line of an old lime tree.

As a clipped or free-growing hedge, it copes just as well in full wind as in a sheltered spot. Its only real requirement is not to be planted in a permanently dark, waterlogged corner: a little light, even filtered, is more than enough for it to thrive.

Watering

Once established, hornbeam more or less does without watering: its deep roots let it find water long after the lawn has gone yellow. Only the first year or two after planting call for real attention, while the root system spreads out, especially if you planted in high summer or on soil that dries out fast.

For a new hedge, a good soak once or twice a week during dry summers is plenty, a deep, spaced-out watering works better than small frequent doses. Past that point, even the recent run of heatwaves has not troubled well-established hornbeam hedges.

Soil and repotting

Hornbeam is not fussy about soil type, and that is exactly what makes it such a safe bet in clay-heavy, damp gardens. Unlike beech, which hates heavy, poorly drained soil and eventually declines in it, hornbeam accepts compacted clay, cool to wet ground, and even land that stays waterlogged for part of the winter.

An ordinary garden soil, neither too poor nor too dry, suits it very well without any special amendment. A little compost at planting helps it get going, but once rooted, hornbeam makes do with whatever it finds, including the heavy, chalky ground that puts off many other hedging trees.

Temperature and humidity

Hornbeam is completely hardy: it shrugs off winters well below minus 20 degrees and takes around minus 30 degrees if it has to, which puts it comfortably in USDA zones 4 to 8. No protection is required, even for a young tree planted at the start of the cold season.

Heat does not trouble it much either, as long as the soil stays cool: increasingly dry summers affect it only marginally once it is well rooted. What does make it struggle is prolonged drought on shallow soil, not the thermometer: under a hot, dry summer climate, plant it in deep soil and water generously for the first few years.

Pruning and upkeep

Hedge trimming is traditionally done in two rounds: a first one once the spring flush stops extending, a second at the end of summer, outside the nesting period which broadly runs from early spring to midsummer. For a hedge that looks crisp all season, the late-summer cut is often the more visible one since it sets the look for autumn and winter.

Hornbeam takes hard pruning remarkably well: you can cut it back hard to rejuvenate an old hedge that has gone bare at the base, and it resprouts from everywhere, even from old wood. That is a rare trait among hedging trees and one of the reasons it turns up so often in traditional clipped hedges around old farms.

Pests and diseases

Hornbeam is one of the healthiest trees you can plant in a garden: it has practically no serious disease of its own, unlike some fussier hedging species. That is a real relief for anyone who has already dealt with fire blight on a photinia or hawthorn hedge.

You may occasionally spot a few aphids on young shoots in spring, a touch of powdery mildew in very humid summers, or defoliating caterpillars passing through and nibbling the leaves without ever putting the tree at risk. None of these problems justifies routine treatment, hornbeam takes it in stride and bounces back without lasting harm.

Propagation

Sowing is the method most commonly used to raise young plants, especially in nurseries growing stock for countryside hedges. The seeds, collected in autumn, need several months of cold stratification before they will germinate, which is why they are usually sown in late autumn or kept in the fridge ahead of a spring sowing.

To plant a hedge, most people buy bare-root trees from a nursery and put them in during dormancy, from leaf fall to bud swell. Allow three to five plants per linear metre depending on how dense you want it, staggered across two rows for a hedge that is properly opaque from the first few years.

Month-by-month care calendar

Green Hub tips

• To stop mixing up hornbeam and beech in a hedge, remember the old nursery rhyme: hornbeam is toothed, beech is hairy. Hornbeam leaves have a ridged surface with a toothed edge, beech leaves are smooth with fine silky hairs along the margin.
• Do not be surprised if the hedge keeps its dried, russet-brown leaves for a good part of winter: that is marcescence, normal in both hornbeam and beech, and it gives you privacy even in the depths of winter.
• Do not replace an old hornbeam hedge that has gone bare at the base, cut it back hard in late winter instead: the tree resprouts from everywhere, even old wood, and fills back in within a season or two.
• Plant bare-root trees during dormancy, never while the sap is rising: allow three to five plants per linear metre to get a dense, opaque hedge quickly.