Growing Rosemary in Scotland: The Complete Guide

Salvia rosmarinus

Everything you need to grow rosemary in Scotland, from a gritty planting hole against a south-facing wall to fresh sprigs for roast lamb all year round. We have done the research so you don't have to.

Rosemary is a Mediterranean shrub that spends its winters in Scotland trying not to drown. It is hardy enough to survive the cold. What kills it is cold wet soil around the roots. The single most important thing you will do for a rosemary plant is dig grit into the planting hole. After that, it is a low-maintenance shrub that gives you aromatic leaves for cooking every month of the year, pale blue flowers in spring that the bees work systematically, and a scent that releases every time you brush past it. A rosemary bush against a warm south-facing wall, in soil that drains freely, will stand for a decade.

Why rosemary needs drainage in Scotland

Rosemary is a drought-tolerant plant from the Mediterranean. It evolved to survive dry summers, not wet winters. In a Scottish garden, the cold is rarely the problem. The wet is. A rosemary plant in free-draining gritty soil, against a south-facing wall that reflects heat and keeps the ground drier, will survive temperatures well below freezing. The same plant in heavy clay that stays saturated through winter will rot at the roots and die before spring. Drainage, not hardiness, decides whether a rosemary survives in Scotland.

Varieties

An upright form gives you the most leaves for cooking; a prostrate form works well in containers and over walls. Miss Jessopp's Upright and Foxtail both carry the RHS Award of Garden Merit, a UK-wide award, not a Scottish one.

Also worth considering

Site and planting

Rosemary needs full sun and well-drained soil. It will tolerate poor dry soil but will not survive wet heavy ground. Choose the sunniest, most sheltered spot you have. A south-facing wall is ideal. The reflected heat keeps the soil drier and the plant healthier.

Plant in spring, once the soil is starting to warm up. Dig a hole wider than the rootball. Mix a generous handful of horticultural grit into the bottom of the hole and into the backfill soil. Do not add compost or manure. Rosemary wants poor gritty soil, not rich damp soil. Space plants 45cm apart if planting a hedge. Water in well after planting and then leave it. Rosemary does not need regular watering once established.

For containers, use a terracotta pot with plenty of drainage holes. Fill with a mix of two-thirds peat-free multi-purpose compost and one-third horticultural grit. Raise the pot on feet over winter so water can drain freely. A pot gives you complete control over drainage, which is the variable that matters most in a Scottish winter.

Care through the season

Once established, rosemary needs almost no care. Do not water it except during prolonged drought. Do not feed it. Rich soil and fertiliser produce soft sappy growth that is more vulnerable to frost damage.

Pruning: trim lightly after flowering in late spring or early summer. Cut just the spent flower stems and any straggly shoots. Never cut into old brown wood. Rosemary does not regrow from bare stems. Regular light trimming keeps the bush dense and productive. Replace the plant every five to ten years as it becomes woody and less productive.

Harvesting: pick sprigs as you need them, all year round. The soft new growth in late spring and summer has the best flavour, but rosemary leaves are usable through winter. Cut whole sprigs rather than stripping individual leaves. The plant responds to regular harvesting by producing more new growth.

Propagation: take semi-ripe cuttings in summer. Cut a 10 to 15cm piece from a non-flowering shoot. Strip the lower leaves, dip in rooting hormone if you have it, and insert into a pot of gritty compost. Keep in a sheltered spot. Roots form in a few weeks. This is also your insurance policy. Take a cutting of your existing plant every few years so you have a replacement growing before the old bush reaches the end of its life.

Common problems

• Root rot from cold wet soil is the main cause of rosemary death in Scotland. Leaves turn brown, usually starting at the base. Improve drainage or move to a drier spot. If the whole plant is affected, it is probably too far gone.
• Rosemary beetle is a small metallic green-and-purple beetle that eats the leaves. Pick them off by hand and drop them into soapy water. Check the undersides of leaves for clusters of small grey larvae.
• Leggy bare stems mean the plant was not pruned regularly. Light annual trims keep it dense. Do not cut into old wood. Start a replacement plant from a cutting if the old one is too woody.
• Yellowing leaves usually mean the soil is too wet. Stop watering. If the plant is in heavy ground, lift it and replant with more grit. Yellow leaves on a rosemary are a drainage problem, not a feeding problem.

Common questions

Sources