When to Plant Trees and Shrubs (and Why Autumn Wins)

Every garden centre is busiest in spring, but ask a nursery grower when they'd plant a tree for themselves and most will say the same thing: autumn. It sounds backwards — planting just as everything is shutting down for the year — yet the plant physiology is firmly on autumn's side. Here's why the season works, when exactly to plant, which plants are the exceptions, and how to get a tree in the ground properly.

Why autumn beats spring for planting

The secret is the mismatch between soil and air. In early autumn the soil is still holding summer's warmth, while the air has cooled and the plant is winding down its leafy top growth. Roots don't follow the calendar — they keep growing whenever the soil is warm enough, well after the leaves have dropped. An autumn-planted tree therefore spends its energy underground, quietly extending its root system for weeks or months before winter properly bites.

Come spring, that tree wakes up already at home, with an established root network ready to power new growth — while its spring-planted neighbour has to grow roots and leaves at the same time, heading into the heat of summer on a root ball the size of its pot. That's also why autumn plantings need dramatically less watering: cooler air, more rain, and no scorching weeks a month after planting. Autumn rain does most of the irrigating for you.

Timing it right

• Deciduous trees and shrubs in containers: from early autumn until the ground freezes, with a comfortable margin — ideally four to six weeks before a hard freeze so new roots can anchor in.
• Evergreens and conifers: early autumn at the latest. They keep their leaves all winter and keep losing water through them, so they need working roots before cold, drying winds arrive.
• Bare-root trees, hedging and roses: any time during full dormancy, from late autumn to late winter, whenever the soil is neither frozen nor waterlogged.
• Borderline-hardy plants in cold regions: wait for spring, so they get a full growing season to toughen up before their first winter.
• Spring-flowering bulbs: the same warm-soil logic applies — autumn is their planting season too.

Warning: never plant into frozen or waterlogged ground. If a delivery arrives during a freeze, keep the plant somewhere sheltered with the root ball moist and covered, and wait for a mild spell. A week or two in a shed does far less harm than planting into concrete-hard soil.

How to plant a tree or shrub properly

• Dig a hole two to three times as wide as the root ball — but no deeper. Wide encourages sideways root growth; deep causes sinking.
• Find the root flare, the point where the trunk widens into the roots, and set it level with (or a touch above) the surrounding soil. Planting too deep is one of the commonest ways trees are killed.
• Tease apart any roots circling the root ball, or slice through them vertically in a few places — left alone, they keep circling and eventually strangle the trunk.
• Backfill with the soil you dug out, not bags of rich compost: roots need a reason to leave the planting hole. Firm gently, don't stamp.
• Water in deeply — around 15–20 litres for a young tree — even if rain is forecast, to settle the soil around the roots.
• Mulch a 5–8 cm layer of bark, compost or leaf mould in a wide doughnut around the base, keeping it a hand's width clear of the trunk itself.
• Stake only if the site is windy or the tree is top-heavy: low and loose, so the trunk can still flex, and remove the stake after a year or two.

Tip: skip the fertiliser at planting time. Feeding pushes soft leafy growth exactly when the plant should be concentrating on roots, and fertiliser in the planting hole can scorch new root tips. If your soil is poor, a mulch of compost on the surface each autumn does the job more gently.

Aftercare until winter

Water deeply once a week through any dry spells until the ground freezes — a slow soak beats a daily sprinkle, because it pulls roots downwards. Before a hard freeze, one last deep watering helps: moist soil holds warmth around the roots far better than dry soil. Then leave the plant alone. No pruning beyond removing damaged branches, no feeding — dormancy is the plan, not a problem.

Good candidates for autumn planting

• Deciduous trees: maples, ornamental cherries, crab apples, rowans, birches and most fruit trees.
• Shrubs: hydrangeas, roses, viburnums, dogwoods, berberis and flowering currants.
• Hedging: beech, hornbeam, hawthorn and yew (yew by early autumn, as an evergreen).
• Plus peonies, spring bulbs and garlic — autumn's warm-soil advantage isn't just for woody plants.

Planting something you inherited with the garden, or a mystery sapling from a friend? Identify it first with PlantMe — the app recognises over 35,000 plant classes from a photo — so you know exactly how much sun, space and hardiness it needs before you commit it to the ground.