This page has very few numbers on it, and that is the honest shape of the answer. Almost everything that kills lavender is a condition rather than a measurement: the drainage, the richness of the soil, the amount of sun, and whether anyone has pruned it.
Lavender is a woody Mediterranean subshrub, not a soft herb you sow each spring. Treat it like basil and it dies. The three things below — sharp drainage, poor soil, annual pruning — are the whole job, and the first two matter most in winter.
Drainage comes first
Winter wet kills far more lavender than winter cold does. This is the single most useful fact about the plant. A lavender sitting in ground that stays saturated from November to March rots at the root and collapses, and the gardener blames the frost. The same variety in gritty, sharply drained soil survives the same winter in the same garden.
So the question to ask about a planting spot is not how cold it gets. It is where the water goes after heavy rain. If puddles sit on the surface for hours, that is not a lavender position.
What to do about heavy ground, in order of how well it works:
- Plant on a mound or a slope so water runs away from the crown rather than collecting round it. Raising the planting position a few inches is often enough on ground that is only slightly heavy.
- Use a raised bed filled with a free-draining mix. What to fill raised garden beds with covers the mix; for lavender, lean the recipe towards the coarse, gritty end and away from compost.
- Use a pot, which gives you complete control of the drainage. More on that below.
Digging grit into a planting hole in clay is the one approach that does not work. It makes a sump: a pocket of free-draining material surrounded by clay, which fills with water and holds it against the roots. Improve a whole bed or raise the plant, but do not dig a well for it.
Poor soil on purpose
The second counterintuitive part: do not feed lavender, and do not plant it in rich ground.
Rich soil and nitrogen produce fast, soft, sappy growth. That growth carries more water in its tissues, stays green later into autumn, never hardens off properly, and is the first thing to rot or blacken in winter. A plant grown hard on poor ground makes short, tight, grey growth that comes through cold and wet far better and flowers more heavily.
This is the same trade-off the marigold page describes, for the same reason, and it is worth stating plainly because every instinct says otherwise: the most common way to look after lavender badly is to look after it too well.
On pH, aim for 6.5 to 7.5, which is the range Utah State gives for English lavender. UGA puts most herbs in roughly the same band and then singles lavender out as one of the few that actually prefers the alkaline end of it, around 7.5 — so lavender's reputation for liking chalky ground is not just garden folklore. What it does not want is acid soil, and if yours is very acid, how to raise soil pH has the sourced quantities.
Sun and position
Lavender wants the most open, sunniest spot in the garden, with air moving through it. Full sun is not a preference here; it is part of the same system as the drainage. Sun and wind dry the foliage and the surface of the soil, and a plant that dries out between rains is a plant that hardens and survives.
In part shade, lavender does not die immediately. It grows longer, softer stems, leans towards the light, flowers thinly, and then fails in its second or third winter. If the only spot you have is shaded for half the day, a pot you can move is a better bet than the ground.
Planting a lavender
Lavender is planted from a container-grown plant, not sown. Seed is slow, variable and will not give you the named variety on the label, which is why almost nobody does it — and why the quick facts table above shows no sowing dates at all, with the reason in each row.
Plant in spring once the ground is workable and hard frost has finished, so there is a full season of root growth before the first winter. On heavy soil, spring is not just better than autumn but a great deal better.
The planting itself is short:
- Water the plant in its pot and let it drain while you dig.
- Dig a hole no deeper than the rootball. Lavender should sit with the top of its rootball level with the soil surface or very slightly proud of it — never in a dip.
- Backfill with the soil you took out, not with compost or manure. Firm it gently.
- Water once, to settle the soil around the roots.
- Then follow the watering schedule below, which is far less water than most people give a new plant.
Spacing is 18 to 24 inches. This is worth flagging because the site's usual note is that two extension services disagree: here Utah State and UGA give the same figure independently, which is as close to settled as a garden spacing gets. The plant spacing calculator turns it into plant counts for a bed.
Lavender is slower than it looks. Utah State puts a mature plant at 1 to 2 feet tall and wide depending on variety, and gives it three years to reach full size — so a young plant that seems to be doing very little in its first summer is usually on schedule.
Watering: much less than you think
This is the figure most likely to surprise you, and it is worth stating as Utah State gives it rather than in the vague terms most lavender advice uses. The schedule has three phases:
- While the plant is establishing: about 1 gallon per plant per week.
- Once established, until flower buds form: about half a gallon every two weeks. Not every week. This is the phase people get wrong, and it is a fraction of what a new shrub usually gets.
- Through flowering: once or twice a week.
The shape of that schedule is the point. Watering drops off sharply after establishment and only picks up again while the plant is flowering. An established lavender given a weekly soak all season is being treated as though it were a soft herb, and the soft, sappy growth that produces is what rots over winter.
Note the unit: Utah State gives this per plant in gallons, not as inches of water over an area, so the quick facts table above reports it that way rather than converting it into a figure nobody published.
Growing lavender in pots
A pot suits lavender well, and on clay it is often the best option available. The rules are the same ones, made easier to follow:
- Use a gritty, free-draining mix. Ordinary multipurpose compost holds too much water. Adding a third of coarse grit or perlite by volume moves it in the right direction.
- Check the drainage holes are actually open, and stand the pot on feet or bricks so water leaves. Never leave a lavender standing in a full saucer, especially in winter.
- Terracotta helps, because it dries through its walls. A plastic pot works if the mix is coarse enough.
- Do not over-pot. A container much larger than the rootball holds a lot of wet mix the roots are not yet using.
The potting soil calculator works out how much mix a given pot takes, and the raised bed soil calculator does the same for a bed.
Potted lavender needs watering in summer — a pot in full sun dries fast, and that is normal rather than a problem. The distinction to hold onto is between a pot that dries out between waterings, which is right, and a pot that stays wet, which is fatal.
Pruning, and why it cannot be undone
Lavender does not reshoot from old wood. Everything else in this section follows from that one fact, and it is the second most common way people lose a plant.
Left unpruned, a lavender grows a little taller each year and leaves behind a lengthening stretch of bare brown wood at the base. Eventually the plant is a woody frame with a thin layer of green on top. The branches splay outwards under their own weight, the middle opens up, and it looks dead in the centre. At that point it is finished: cutting back into bare wood to make it bush out produces nothing, because there are no dormant buds there to shoot from.
Preventing it is easy and takes a few minutes a year, and Utah State puts a number on how hard to go: shear the plant back to half its size, once a year, after it has flowered. That is a good deal more than most people dare take off, and taking off too little is exactly how a plant creeps upwards into bare wood over several seasons.
The one limit on that is the wood itself. Always cut into growth that still carries leaves, never into the bare brown wood below — halving a plant that has been pruned every year since it went in stays comfortably within leafy growth, which is the reason to start in its first year rather than its fifth.
A plant that has already split open cannot be rejuvenated. You can sometimes fill the gap by pegging a low branch down to root, or take cuttings from the green growth and start again, but the original plant will not come back. Replacing it is not a failure; it is the plant's habit.
Salvia versus lavender
These two get confused constantly at the garden centre, and often enough for it to be a search of its own. Both are in the mint family, both make spikes of purple-blue flowers, and both get sold on the same bench in early summer.
The differences worth knowing:
- Leaves and scent. Lavender has narrow, grey-green, strongly perfumed leaves. Most ornamental salvias have broader, softer, mid-green leaves with a savoury, herbal smell rather than a perfumed one.
- Habit. Lavender is woody from the base up and keeps its frame through winter. Many salvias are softer and more herbaceous, and several are grown as tender plants replaced each year.
- Flowering length. Salvias generally flower for much longer through the season; lavender flowers heavily in a shorter window.
- Soil. Salvias are far more forgiving of decent, moisture-holding soil than lavender is.
Rosemary makes this worse rather than better: it has been reclassified as Salvia rosmarinus, so rosemary genuinely is a salvia now, while lavender is not and never was. Our rosemary guide covers that plant.
What a "lavender tree" actually is
A lavender tree is not a species or a variety. It is an ordinary lavender — very often a tender one — trained as a standard: a single clear stem with a rounded head of growth on top, produced by rubbing out the side shoots as the plant grows.
Everything on this page still applies: the same drainage, the same poor soil, the same annual pruning of the head. What changes is exposure. The head sits up on a thin stem where the wind gets at it, the pot is usually small relative to the plant, and it dries out and blows over more readily. Stake the stem, give it some shelter, and expect to water it more often than a plant in the ground. Many standards sold this way are tender varieties that need protecting over winter — check the label before leaving one out.
Lavender leaves: what they tell you
The leaves are the first place trouble shows, and they are searched for on their own.
Grey-green and narrow is healthy. Lavender leaves are supposed to look silvery and dry rather than lush.
Soft, large and bright green means the plant is being fed or grown too richly, or has too little light. Expect thin flowering and poor winter survival.
Blackening, or browning from the base upwards, with soft stems is usually rot from wet soil. By the time the foliage shows it the roots are normally gone.
Grey, dry, brittle stems in the centre of an older plant is the woody-base problem in the pruning section above, not a disease.
Lavender companion plants
Lavender's real companions are plants that want the same conditions, which is a more useful test than any traditional pairing list. Anything that needs the sharp drainage, full sun and poor soil lavender needs will thrive beside it; anything that wants rich, moist ground will either struggle or, worse, get watered and fed in a way that kills the lavender.
That puts the other woody Mediterranean herbs at the top of the list — rosemary, thyme and sage all share lavender's requirements closely enough to be planted together with no compromise. Soft herbs are the opposite case: basil wants warmth, moisture and regular feeding, so it belongs in a different bed or a different pot rather than next to a lavender.
Lavender in flower is heavily worked by bees and other pollinators, which is the usual reason it is planted near a vegetable garden. That is a real effect and an easy one to observe. Claims that it repels particular pests from neighbouring crops are the weaker end of companion planting — the pollinator traffic is the part you can rely on.
The quick facts table above lists our companion and keep-apart entries, and the note under it is worth reading: companion planting is traditional practice rather than settled science, and getting the drainage right will do far more for a lavender than its neighbours ever will.
Common problems
The plant collapsed over winter. Almost always rot from wet soil rather than cold. Check where water sits in that spot before replanting, and raise the next one.
Lots of leaf, few flowers. Too rich, too well fed, or not enough sun. Stop feeding entirely; the plant will not need it.
Bare and woody at the base, open in the middle. Years without pruning. Not fixable — see the pruning section.
Nothing came from the cutting. Lavender roots readily from soft growth in summer, but cuttings rot in a mix that holds water. The same rule as the parent plant applies.
It died in a pot. Look at the saucer and the drainage holes first, before anything else.
Our other herb guides cover the soft annuals this plant is nothing like: basil, dill and parsley. The full set is on the crop guides index.