Three conifers, three very different habits

Walk down any British lane and you can usually spot the difference from a distance. Yew makes a dark, dense, almost architectural wall that has been clipped into shape for decades. Pine stands tall and airy, with a reddish trunk and a canopy that begins well above head height. Spruce forms a tight green cone, often planted in rows as a windbreak on a hillside where nothing else will hold.

All three are evergreens, all three are conifers, and all three can be used in a garden boundary — but they behave very differently once they are in the ground. Yew clips beautifully and tolerates shade. Pine needs space and light. Spruce gives you a dense screen quickly, provided the soil suits it. Getting the match right at planting time saves years of disappointment later.

Yew: slow, forgiving, and happy in shade

Yew (Taxus baccata) is the classic British hedging conifer, and for good reason. It grows at roughly 20–30cm a year once established, which sounds slow until you realise that means a neatly controlled hedge you are not fighting every summer. It is one of the very few conifers that will regenerate from old wood, so you can cut a yew hedge back hard into bare branches and it will usually shoot again.

It is also the best of the three for shade. A north-facing boundary or a strip beneath mature trees is where yew earns its keep. It tolerates chalk, clay and most soils that drain reasonably, and it lives for centuries — a hedge planted now may well outlast the house.

• Clipping: once or twice a year, June and again in late September if you want crisp edges.
• Height range: anything from 1m to 4m with regular trimming.
• Watch out: every part except the red aril around the seed is toxic to livestock, horses and dogs, so avoid planting alongside grazing paddocks or where hedge clippings might end up in hay.

Pine: magnificent, but it needs room to breathe

Pines are not hedging conifers in the conventional sense. Scots pine (Pinus sylvestris) wants to become a 15–20m tree with a taproot, a bare trunk and a crown of blue-green needles that filters light rather than blocking it. Plant a row of them 60cm apart and you will not get a hedge; you will get a forest.

Where pine works is as a shelterbelt or a boundary screen on a large plot, or in its smaller forms such as dwarf mountain pine for a low, spreading, ground-covering mass. It insists on light and good drainage, dislikes heavy clay and waterlogging, and resents being moved once it is any size — always plant it small.

• Spacing for a screen: 2–3m between trees, allowing them to develop naturally.
• Pruning: only ever into green needles, and only while the tree is young. Pines do not shoot from bare wood.
• Side effect: the needle litter is acidic and slow to break down, so little grows beneath a mature pine.

Spruce: the fast, dense conical screen

Norway spruce (Picea abies) is the one to choose when you need a solid, dark green barrier in a hurry. It grows quickly, holds its lower branches well when young, and its natural conical shape makes a dense screen that blocks wind and sightlines almost from the start. Sitka spruce is even faster and tougher, which is why it clothes so many exposed western hillsides.

The catch is that spruce is less forgiving than yew. It does not regrow from old wood, so a hedge must be trimmed lightly and regularly rather than cut back hard. It also wants moist, free-draining, neutral-to-acid soil. On thin chalk or in dry shade it will sulk, drop its inner needles and turn leggy — the classic brown, see-through spruce hedge seen on the wrong site.

• Spacing for a screen: 60–90cm apart, planted in a single row or staggered double row.
• Clipping: trim the sides lightly each year and, if you want a hedge rather than a tree, take out the leader in spring while it is still green.
• Watch out for spruce aphid, which causes yellowing and needle drop in mild winters.

Matching the species to your soil and site

Before you buy anything, do two simple checks. First, dig a hole about a spade deep and fill it with water to see how quickly it drains. Second, note how many hours of direct sun the boundary receives and whether the soil is acid, neutral or chalky.

• Deep shade, chalk or clay, and a desire for a formal clipped line: yew.
• Large plot, sandy or acid soil, plenty of light, and space for big trees: Scots pine.
• Moist, slightly acid soil, an exposed site, and a screen needed quickly: spruce.

If you are on chalk in a dry, sunny garden and want a dense screen, spruce will disappoint you and pine will need more room than most boundaries allow. That is the honest answer, and it is worth knowing before you spend a weekend planting.

Planting distances and the first three years

Bare-root conifers planted between late October and early March establish far better than pot-grown ones bought in June, and they are considerably cheaper for a long run of hedging. Water them well in the first two summers, keep a metre-wide strip clear of grass and weeds, and mulch with well-rotted bark or compost — but keep the mulch clear of the stems.

Yew hedges are usually planted at 45–60cm apart for a 2–3m hedge. Spruce screens go in at 60–90cm. Pines, if used as a screen at all, need 2–3m. Feed lightly in the second spring, resist the urge to clip hard in the first two years, and let the roots settle. After that, all three will reward you with decades of green structure that no fence can match.