Lavender care in pots, for a sunny balcony
Lavender wants full sun, a gritty mix that dries quickly and a trim as soon as it finishes flowering. That makes it a balcony or terrace plant. This page covers which kind you have, how to water and prune it in a pot, and what to do with it over winter.
- Give it full sun outdoors, on a balcony or terrace. A wall inside a room is too dark.
- Water only when the mix is dry a finger deep, and keep it drier in winter.
- Trim it just after flowering, and never cut into the bare woody stems.
English, French or Spanish lavender, and how to tell them apart
Lavender sold in a pot is one of three kinds, and the flower head tells them apart. English lavender carries slim spikes with nothing on top. Spanish lavender carries a fat head topped by two upright bracts, which NC State Extension compares to rabbit ears.
French lavender is the confusing name. NC State and the RHS both use it for the topped Spanish kind, and shops also sell Lavandula dentata under it, a plant the RHS describes with narrow leaves and finely lobed edges. A toothed leaf edge means dentata.
The kind decides how hard you can trim the plant and whether it can stay outside through a frost. The plant care guide sets every other plant on the site side by side by the light and water it takes.
| Kind | How to spot it | Hardiness | Pruning |
|---|
| English lavender, Lavandula angustifolia | Slim spikes of small flowers with nothing on top | The hardiest, usually stays out all winter | Trim after flowering, never into old wood |
| Spanish lavender, Lavandula stoechas | Fat flower head topped by two upright bracts | Less hardy and short-lived | Shear lightly after flowering, never to the ground |
| French lavender, Lavandula dentata | Narrow leaves with finely lobed, toothed edges | Hardy only in mild coastal areas | Trim after flowering, never into old wood |
How much sun lavender needs
Full sun, meaning direct sun on the plant for most of the day. NC State defines full sun as six or more hours of direct sun and lists both English and Spanish lavender under it. The RHS adds that lavender will not survive long in shady, damp or very cold conditions.
On a building that means a balcony, terrace or roof facing south or west, with the pot at the height where the sun actually lands. A wall that is bright but never gets a direct beam counts as shade to this plant. It shows slowly, as fewer flower spikes each summer, and NC State names too little sun as a cause of poor flowering.
All three kinds grow wild around the Mediterranean, NC State and the RHS agree. A hot balcony in full sun is close to the conditions they come from.
Can lavender grow indoors?
Only at a sunny window, and even there only as a temporary stay. The UC Master Gardeners give the indoor minimum as five to six hours of bright light from a sunny window, or grow lamps running fourteen to sixteen hours a day.
A wall inside a room rarely gets that, because the direct beam from a window lands on the sill and the floor near the glass. A plant short of light also uses less water, so the mix stays wet for longer. If the wall you want to plant is indoors and away from the glass, a Pothos takes that spot.
So grow it outside and choose something else for the room. Low light houseplants covers which plants live on an indoor wall that the sun never reaches.
How often to water lavender in a pot
Water when the mix is dry a finger deep, then water thoroughly and let it dry again. NC State asks for soil on the dry side and names overwatering as the cause of root rot.
Sun sets the pace. A small container in full summer sun dries fast, and the RHS notes that lavender in pots needs regular water in summer for exactly that reason. The same pot in winter, with weak sun and cool air, stays damp for a long time, and that is when the roots rot.
A pot in full summer sun cannot go unwatered for long, so a trip away needs a plan. DIY drip irrigation compares the bottle, bucket and tubing setups that keep one going.
Soil, grit and feeding for lavender in containers
A peat-free compost with coarse grit mixed through it, and no feed. The grit is what lets water leave the roots, which matters more in a container than in open ground.
- The mix. Peat-free multipurpose or loam-based compost, with coarse grit up to a quarter of the volume. That is the RHS figure for containers.
- Drainage. NC State asks for perfectly drained soil for English lavender and excellent drainage for Spanish. Heavy, wet compost is what both pages warn against.
- Feeding. None as a rule. The RHS says lavender likes soil low in nutrients, and NC State lists excess nitrogen as a reason Spanish lavender flowers poorly.
- Planting depth. Set the plant at the same level it sat in its nursery pot, as the RHS advises.
How to prune lavender after flowering
Trim it once a year in late summer, as soon as the flowers fade, and stop above the bare wood. The RHS advises removing the spent flower stalks plus about 2.5 cm of leaf growth, and warns that lavender does not regrow well from old wood.
That last point decides how the plant ages. Left untrimmed it turns woody and opens up from the middle, and once green growth sits only at the tips there is nothing left to cut back to. The RHS says such a plant is best replaced, and NC State warns that Spanish lavender dies if it is cut back to the ground.
- Wait until the last spikes have faded, in late summer.
- Cut every spent flower stalk down to the leafy growth.
- Take off about 2.5 cm of that leafy growth as well.
- Stop wherever you reach grey bare stem, and leave the green shoots below it.
- In spring, clip over any growth that is untidy or frost damaged.
Lavender in winter, outdoors or brought in
English lavender stays outside all winter, and the French and Spanish kinds need a frost-free spot wherever winters bring frost. The RHS calls English lavender usually hardy in free-draining soil, and grows the tender kinds in containers so they can be moved.
In a pot, winter wet is the risk to manage. The RHS advises keeping containers fairly dry over winter, for example in the rain shadow at the base of a wall, which is where a pot on a sheltered balcony wall already sits.
If a tender kind has to come in, give it the sunniest window you have and water it sparingly until spring. Put it back out once the frosts are over.
Is lavender toxic to cats and dogs?
Yes. The ASPCA lists lavender as toxic to dogs, cats and horses, names linalool and linalyl acetate as the toxic principles, and gives nausea, vomiting and loss of appetite as the signs.
NC State places those compounds in the flowers, leaves and stems, so fallen flower spikes on a balcony floor count as well. Keep the pot where the animal cannot reach it. If it has been chewed, call a vet or the ASPCA Poison Control line rather than waiting to see what happens.
Lavender on the wall
Lavender belongs on an outdoor wall, on a sunny balcony or terrace, and the canvas works there as long as the wall is sheltered. The pocket is recycled PVC with a geotextile layer inside and takes the weather. The wooden board is the part that must stay out of standing rain. Other ways to plant an outdoor wall are compared in living wall systems.
The Medium pocket holds 1.8 litres of substrate, about what a 15 cm pot takes. The RHS grows a lavender in a container 30 to 40 cm across, so the pocket suits a young plant of a compact kind, such as the English cultivar Hidcote Blue, until it fills the pocket and moves on to a bigger pot. The Small and Mini pockets hold 0.45 and 0.23 litres, which is room to root a cutting.
The board hangs by a slot near its top on one wall hook, so the wall takes one hole, drilled or nailed. An outdoor wall is usually brick or render, which takes a drill and a standard plug, and the mounting steps start there.
- Mix coarse grit through the substrate before you fill the pocket.
- Take a young lavender out of its nursery pot and loosen the roots.
- Set it at the depth it grew before and fill around it.
- Water slowly, in measured amounts, then let the top dry before the next watering.
Lavender problems and how to fix them
Wet roots are the problem NC State, the RHS and the UC Master Gardeners all list, and they show first at the base of the stems. A plant that greys and softens from the bottom up is rotting, and it needs drier mix today.
Pests are a smaller matter on this plant. NC State lists aphids, spider mites, whiteflies and thrips on Spanish lavender, and the RHS says the rosemary beetle and the leafhoppers found on lavender cause only cosmetic damage.
| What you see | Why | The fix |
|---|
| Stems soft and grey at the base, plant collapsing | Root or crown rot from compost that stays wet | Stop watering, cut away soft roots and repot into gritty mix. |
| Few or no flower spikes | Too little direct sun, or a feed high in nitrogen | Move it into full sun and stop feeding. |
| Bare woody centre, splayed open | Several seasons without a trim | Replace it, and trim the new plant every late summer. |
| Dead patches after winter | Wet compost through the cold months, or frost on a tender kind | Keep the pot fairly dry and sheltered over winter. |
| Pale speckled leaves, fine webbing | Spider mites | Rinse the plant and check the leaf undersides weekly. |
| Spots on the leaves | Leaf spot, in still damp air | Give the plant more space so air moves around it. |
How to propagate lavender from cuttings
Cuttings are the reliable route, because the RHS notes that seed from a named cultivar can come up different from the parent. Take softwood or semi-ripe cuttings from a young plant in early to midsummer, or hardwood cuttings after flowering in late autumn.
- Choose a young shoot with no flower on it.
- Cut it just below a leaf joint with a clean blade.
- Strip the leaves from the lower part so none sit below the surface.
- Push it into a small pot of gritty, peat-free cutting compost.
- Keep it in bright light out of the midday sun, with the compost barely damp.
- Pot it on into gritty mix once new growth shows at the tip.
Take the cuttings the summer before you plan to replace an old woody plant. The young one is then ready by the time the old one has gone past pruning.
Does lavender come back every year?
English lavender does. It is an evergreen shrub that stays out through winter in free-draining soil. The RHS calls the French and Spanish kinds less hardy and short-lived, so a hard frost or a wet winter can end them.
Why is my lavender turning yellow?
Yellowing that starts low on the plant and comes with soft stems points to wet roots, the rot NC State links to overwatering. Let the mix dry and feel the base of the stems for soft tissue. The other causes, on any plant, are in what yellow leaves are telling you.
Which lavender is used in cooking?
English lavender. NC State lists Lavandula angustifolia as edible, and advises against Spanish lavender in the kitchen because of its strong camphor flavour.
Can I hang lavender on a balcony wall without drilling?
The canvas needs one hole for its single wall hook, drilled or nailed. A drill-free fixing has to hold the pocket at its wet weight, and hang plants without drilling covers what each fixing holds.
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