Where and How to Plant Rosemary So It Lasts for Years

Choose the spot for drainage first, sun second

Before you dig, watch where water sits after heavy rain. Anywhere a puddle stands for more than an hour, or the soil stays dark and sticky a day later, will kill a rosemary within a couple of winters. A slope, the top of a bank, the edge of a path or a raised bed are all better than the middle of a flat bed.

Then look at the sun. Full sun for most of the day, with shelter from cold drying wind, gives you a dense aromatic bush. A south or west facing wall is close to ideal: it gives light, reflects warmth back at night, and keeps the worst of the winter wet off the crown.

1. Test the drainage before you commit Dig a hole a foot (30 cm) deep, fill it with water and let it drain, then fill it again. If the second filling has not drained within four hours, the site is too wet for rosemary planted at ground level.
2. Keep it off irrigated beds Rosemary planted among annual vegetables gets watered on their schedule, not its own. Give it a corner, a border edge or a bed of its own where you can leave it dry.
3. Allow the full size An upright plant reaches three to five feet (90 to 150 cm) across in time. Planting it eighteen inches from a path means cutting it back hard every year, which shortens its life.

Plant in spring so it roots before winter

The best planting window is spring, once the soil has warmed and the last hard frosts have passed. That gives a full season for roots to spread before the plant has to face cold wet soil. Early autumn planting works in mild gardens, but a young plant that goes into cold ground with a small root system is the one that fails over winter.

Avoid planting in the middle of a heatwave. A new plant cannot draw enough water through a disturbed rootball, and you end up watering it heavily to keep it alive, which is exactly the treatment rosemary least tolerates.

Plant high, and do not enrich the hole

Dig a hole a little wider than the rootball but no deeper. Set the plant so the top of its rootball sits about an inch (2 to 3 cm) proud of the surrounding soil, and slope the soil up to meet it. Planted level or slightly low, the crown collects water every time it rains and the base of the stem rots.

Resist the instinct to fill the hole with compost or manure. Rich soft soil in a pocket surrounded by firm ground creates a sump that holds water, and it encourages fast sappy growth that will not harden off. Backfill with the soil you took out, improved only with grit if the ground is heavy.

1. Tease out circling roots If the rootball is a solid mat of roots running round the pot shape, pull the outer ones loose with your fingers. Left circling, they never grow out into the surrounding soil and the plant stays stunted.
2. Backfill and firm gently Fill in with the native soil, pressing lightly with your hands rather than treading. Heavy compaction squeezes out the air the roots need.
3. Water once, thoroughly Give it a full watering to settle the soil around the roots, then leave it. That first soaking removes air gaps far better than repeated light watering.
4. Mulch with grit, not bark Spread an inch of gravel or coarse grit over the root area, keeping it clear of the stem. It suppresses weeds and keeps the crown dry, where bark mulch would hold moisture against it.

Write down where you planted each bush and how the drainage behaved that first winter. Rosemary rarely dies quickly, so being able to compare two positions after a couple of years is the only reliable way to learn which corner of your garden actually suits it.

The first season is the only one it needs watering

For roughly the first two months, water when the top two inches (5 cm) of soil have dried, giving a good soaking rather than a sprinkle. Deep, infrequent watering draws roots downward; frequent light watering keeps them near the surface, where they are the first to suffer in drought and the first to freeze.

After that first summer, stop. An established rosemary in open ground should get nothing but rainfall except in an exceptional drought, and even then a single deep soak a month is plenty. The signal to water is dull, slightly limp needles, not a dry surface.

Do not tip the plant out to check the roots if it looks slow in its first weeks. Rosemary puts its effort below ground first, and top growth often does not visibly move for a month after planting.

Spacing and companions

Give an upright plant three feet (90 cm) of clear space in each direction, and a spreading form at least the same, since it will trail sideways rather than up. Planted closer, the bushes shade each other, air stops moving between them and mildew follows.

Grow it alongside other dry-soil, sun-loving shrubs and herbs so the whole bed can be managed on one regime. What it should not share a bed with is anything that wants steady moisture and rich soil, because you cannot water two such different plants from the same can.