Hedgerow

A hedgerow is a dense line of shrubs and trees along a boundary. It screens the edge, slows the wind and gives wildlife a sheltered route between patches of cover. It is mixed species at mixed heights, not one clipped hedge: one row is the minimum, several rows and 6 m (20 ft) or more where habitat is the aim. Its flowers feed wild bees, most of which nest in bare ground, so open soil beside it matters as much as the planting itself.

Wind is the effect that arrives soonest: at about half porosity - half solid, half gaps, so air is slowed rather than blocked - a two-row planting drops drifting snow over roughly ten times its height downwind, and a fast-growing species works within a season of cutting. Ground-nesting bees reach a crop only within about 300 to 1000 m (1000 to 3300 ft) of the nest, so a hedge too far off delivers nothing. Crops beside a hedgerow suffer less pest damage, but the useful insects work in the crop rather than live in the hedge, so it carries them between outbreaks rather than housing them.

A hedgerow does not exclude deer. Once food is short they eat most plants, even ones sold as deer-resistant; only a fence 2.1 to 2.4 m (7 to 8 ft) high, taller on a slope, reliably keeps them out. It is weakest in the drought and heavy browsing that make exclusion urgent, so it belongs beside a fence rather than instead of one - and the cover it gives pollinators it gives rodents too. The costly years are the first three: new stock needs 8 to 19 litres (2 to 5 gal) per plant every two or three weeks in dry spells, plus weeding, and most losses fall before any benefit arrives. After that it is cut, mowed or laid every ten to twenty years, slow enough to forget until it has gone leggy, with one job in between: keeping wide shrubs from shading out the flowering plants, since the screen survives that and the bees do not. The cuttings are material, not waste.