Tree · Meliaceae
Neem Tree
Azadirachta indica
Give it heat, sun, and free-draining soil and the neem tree will forgive drought and poor ground and thrive for decades.
Full sun
Every 7–21 days
USDA 10–12
50–75 ft · 15.2–22.9 m
Overview
Neem is a fast-growing evergreen from the mahogany family, at home in south Asia and now planted across the warm reaches of Asia and Africa. Leave it be and it grows into a wide, shady tree, and it gets there quickly, so a nervous first-timer can take real comfort in how eager it is to grow. People have relied on it for generations, from chewing the twigs to pressing the seeds for oil.
The part that makes neem special in a garden is its seed oil. Those seeds are rich in azadirachtin, a compound that puts insects off their food and unsettles their growth and breeding, which is why gardeners turn neem into a gentle natural pesticide. The leaves carry a long medicinal tradition of their own, and they are far kinder than the concentrated oil.
Once it has settled in, neem asks very little of you, which is exactly what makes it so forgiving. It takes heat to 113°F (45°C), brushes off drought, and grows in poor, rocky, even mildly salty ground. Its one real weakness is cold, since frost cuts it back and a hard freeze can kill it, so it stays outdoors only in the warmest zones.
Care
The short version: give it full sun and warmth, deep well-drained soil, and a good deep soak for young trees during dry spells while you let the surface dry between waterings. Once it is established it takes on drought and poor ground by itself, and the only thing you must spare it is frost.
Light
Give neem full sun and it will grow fastest out in the open, though it happily puts up with partial sun or light shade. The more direct light you can offer, the denser and stronger the crown comes in.
Water
Water young trees deeply through dry spells, then let the top half of the soil dry before the next drink, which lands roughly every 7 to 21 days. Once neem has settled it stands up to real drought, and the single thing it will not forgive is waterlogged ground.
Soil
Plant into deep, well-drained sandy or loamy soil and you are off to a good start. Neem is easygoing and copes with poor, rocky, and mildly salty ground, working across a wide pH band of 6.0 to 8.0. Drainage matters most of all, because the roots rot in soil that stays wet.
Temperature
This is a tropical to subtropical tree, glad of heat right up to 113°F (45°C). The tender edge is the cold end, around 41°F (5°C), below which frost scorches the leaves and a freeze can take a young tree.
Humidity
Average humidity keeps it content, somewhere in the 40% to 70% range, and it takes the dry air of semiarid regions in stride. There is no misting or fussing over moisture needed here, which is one less thing to worry about.
Feeding
Feed through spring and summer with a balanced slow-release fertilizer or compost, and once a season is all it takes. Neem does well in lean soil, so a heavy hand at feeding does more for pests than for the tree by pushing out soft, sappy growth.
Pruning
Prune in late winter to early spring to shape the crown and clear out any dead, damaged, or crossing branches. Neem takes hard pruning and even pollarding without complaint, which makes it a forgiving choice for a clipped hedge.
Repotting
A container-grown neem wants repotting every 2 to 3 years while it is young, before the roots circle and crowd the pot. In a frost-free climate the kinder long-term move is to plant it straight into the ground.
Size & spacing
A mature neem is a genuinely big tree, reaching 50 to 75 feet (15 to 23 m) tall with a broad canopy that can spread 40 to 60 feet (12 to 18 m) across. Give it plenty of open room and keep it well clear of buildings, paving, and smaller plantings.
When to plant
Neem lives on warmth and simply will not survive frost, so a little planning goes a long way. Sow fresh seed in late winter or early spring under cover, set young trees out in spring once the soil has warmed and the cold has passed, and look forward to fragrant white flowers in spring followed by olive-like drupes from summer into early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring in frost-free warmth; sow fresh seed because viability is short
- Plant: Spring after all danger of frost, once soil is warm
- Harvest: White fragrant flowers in spring; olive-like drupes ripen summer to early fall
Hardiness
USDA hardiness zones: 10–12
Temperature: down to -1°C
Troubleshooting
Grown in the right climate a neem gives you very little grief, so most troubles come down to cold, soggy soil, or sap-sucking pests. Learn to read the early signs on the leaves and roots and you can step in long before anything spreads. Match what you see below, then act while your help still counts.
Drooping, yellowing leaves paired with mushy dark roots
A neem sitting in soggy ground that starts to wilt and yellow is usually telling you about root rot, and this one is worth catching early. Ease back the soil and healthy pale roots will have turned brown and mushy. There is no fix once it takes hold, so the kind thing to do is stop the overwatering, sort out the drainage, and give the tree a fresh start in deep, sandy soil that dries at the surface between waterings.
Fix:
- Improve drainage and stop overwatering
- Remove affected plant material
- Replant in deep, sandy, well-drained soil
Browned foliage and dying branch tips once the cold hits
If a cold snap leaves you looking at browned foliage and dead branch tips, take heart, because this is the common story with a tropical tree that simply cannot take frost. The harm settles on the exposed outer leaves once it dips below about 41°F (5°C), and neem stays happy only in zones 10 to 12. Wait for the frost danger to pass, trim away the dead wood, and shelter young trees or keep them potted so you can carry them indoors when the cold rolls in.
Fix:
- Prune out dead wood after the danger of frost has passed
- Protect young trees with frost cloth or grow in containers that can be moved indoors
- Site in a warm, sheltered location
A sticky black film spreading over the foliage
That dark film is only sooty mold, and it settles on the sugary honeydew that scale, whitefly, or aphids leave behind as they feed. Look over the shoot tips and leaf undersides for the little insects doing the real work, because the mold itself does no harm and lifts off with an easy wipe. Give the leaves a rinse, treat the pests with horticultural soap or oil, and let the garden's natural predators finish the job for you.
Fix:
- Rinse foliage and wipe off mold
- Control the sap-sucking insects with horticultural soap or oil
- Encourage natural predators
Toxicity
The leaves are low in toxicity and carry a long history of medicinal use, so a curious nibble is rarely a reason to worry. The care you do need is around the concentrated neem oil and the seeds, which are rich in azadirachtin and can make pets and people unwell if swallowed in quantity. Cats feel it the most, so keep the oil and seed products stored well out of reach and you will have covered the risk.
Toxic to
Cats · Dogs · People
Safe for
Horses · Rabbits · Livestock · Birds
Cats Mild
You can relax about the leaves, which are low in toxicity, but cats are the ones most sensitive to concentrated neem oil. Swallowing the undiluted oil or being treated with it can bring on drooling, vomiting, and a listless cat, and reported cases stretch to tremors, twitching, and convulsions. Just tuck the seed oil and extracts somewhere a cat can never reach.
Dogs Mild
A nibbled leaf hardly ever causes a problem, so no need to panic there. The thing to watch is the concentrated oil, which can trigger vomiting, drooling, and a dull, sluggish dog if it gets swallowed or slathered on too heavily. Dogs cope with diluted topical neem more comfortably than cats do.
People Caution
Neem leaves carry a long history of medicinal use and are low in toxicity, so those are the easy part, but the concentrated oil and the seeds call for real care. Swallowing them in quantity can bring on vomiting and worse, and that risk climbs highest for small children, so keep neem oil and seed products stored safely.
Horses Safe
A grazing horse has little to fear from the foliage. All you need to do is keep the concentrated neem oil and seed products where a horse cannot get at them.
Rabbits Safe
Browsed leaves sit low on the toxicity scale for rabbits. Any real trouble would come only from the concentrated oil or a mouthful of crushed seed, and neither is something a rabbit should ever be able to reach.
Livestock Safe
Cattle, goats, and sheep browse neem foliage with little worry, and across parts of its range the leaves even serve as fodder. The one thing to hold back is the seed oil, which should not be fed to them.
Birds Safe
Birds face no particular danger from the leaves or the fruit. Simply keep them clear of any concentrated oil or extract and all is well.
Keep concentrated neem oil and neem seed products away from pets; never apply undiluted neem oil to a cat or dog or allow them to ingest it.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Neem comes in two main forms, one raised for the kitchen and one for its potent seed oil. These are the two worth telling apart.
Azadirachta indica var. siamensis (Thai neem)
This gentle Southeast Asian form grows young leaves and flowers mild enough to serve as a vegetable, a welcome change from the common type that stays far too bitter for the plate.
Common neem (typical var. indica)
The widely grown South Asian type wins its keep through azadirachtin-rich seed oil, which gardeners press into a friendly botanical biopesticide.
Companions
Neem earns its keep near vegetable and fruit crops, where its leaf and seed extracts deter many garden pests, but its dense shade, hungry roots, and allelopathic leaves make poor company for small plants growing right beneath it.
Plant near
Vegetable and fruit crops: Neem leaf and seed extracts are used as a botanical biopesticide that deters many garden pests.
Keep apart
Shallow-rooted understory plants: Its dense shade, vigorous roots and allelopathic leaf compounds suppress small plants growing directly beneath it.
How to propagate
Neem is an easy tree to multiply, nearly always from seed, with cuttings kept in reserve for when fresh seed is not around or you would like a copy of a particular tree.
SeedEasy
Sow fresh seed in spring in warm conditions · Germinates in 1 to 3 weeks; transplant after a few months
Most gardeners raise neem from seed, and the one thing to get right is timing. The seed loses its life fast, so sow it soon after the fruit ripens, in the warmth of spring. Give it a little patience and it sprouts in 1 to 3 weeks, ready to move on after a few months.
Stem cuttingsModerate
Warm season from semi-hardwood cuttings · Roots in several weeks under warmth and humidity
When no fresh seed is at hand, or you would love a copy of a favorite tree, reach for semi-hardwood cuttings taken in the warm season. Keep them warm and humid and they settle in, rooting over several weeks.
Myths
Because neem oil comes from a plant, it is bound to be gentle on any pet.
Being natural does not make it harmless, since its active compound azadirachtin can set off drooling, vomiting, and tremors, and the concentrated oil has made cats seriously ill and in some reported cases proved fatal. Reach only for heavily diluted oil, and keep the concentrate well away from your animals.
Neem wipes out any bug the moment it makes contact.
It works with more patience than that, mostly putting insects off their food and unsettling the way they grow and breed, so results build over days rather than the moment of contact. Think of it as thinning a pest population little by little, not flattening everything on the spot.