Tree · Juglandaceae
Pecan
Carya illinoinensis
Give it room, full sun, and a pollination partner, and a pecan shades the yard for generations.
Full sun
Every 7–14 days
USDA 6–9
66–131 ft · 20–40 m
Overview
A pecan grows into a long-lived shade tree that throws in a nut crop as the payoff. It runs in the walnut family and hails from the river valleys of the south-central United States, where it stretches into a broad, towering canopy. Plant one and you set roots down for the long haul, because a healthy tree can carry on for a hundred years or more.
Size drives every planting call. A mature pecan powers up to 66 to 131 feet (20 to 40 m) tall with a spread to match, so it wants open ground kept well back from houses, walks, and power lines. The wood runs brittle and casts off limbs in ice and wind, one more nudge to hand it plenty of room.
The nuts reward the grower who plays the long game with a partner in the ground. Pecans are wind-pollinated and stagger their pollen and flowers, so a single tree pollinates itself poorly, which is why two compatible cultivars crop so much harder than one. Fold in the tree's hunger for zinc and its long climb to a first harvest, and a pecan pays back the gardener who thinks in years, not seasons.
Care
The short version: full sun and deep, well-drained soil, with room to spare for a huge tree. Water deeply but not often, feed with nitrogen and zinc through the growing season, and plant a second cultivar nearby for pollination.
Light
Pecans crave full sun to crop hard, ideally 8 or more hours a day. A young tree puts up with a bit of partial sun, but heavy shade leaves you a thin canopy and a scant handful of nuts.
Water
Water deeply but not often, and let the top half of the root zone dry between soakings. Young trees drink in regular deep watering to settle, and even mature trees crave a long soak through nut fill and the late-summer dry stretch. Shallow, frequent sprinkling backfires and does more harm than good.
Soil
Set a pecan into deep, fertile, well-drained sandy loam to loam. It brushes off the odd flood but rots in standing water, and it favors a pH between 6.0 and 7.0, which also keeps zinc within reach of the roots.
Temperature
Pecans power through a wide swing, from about -4°F to 104°F (-20°C to 40°C), which lines up with the long, hot summers they need to ripen nuts. That deep cold tolerance lets them ride out winter once they drop into dormancy.
Humidity
These trees thrive across 40% to 70% humidity, so skip chasing a number outdoors. Warm, humid air does egg on scab, which is why airflow and resistant cultivars carry far more weight than the reading itself.
Feeding
Feed from early spring through early summer with a balanced nitrogen fertilizer, then push zinc in by soil or foliar spray. Zinc shortage runs common in pecans and flares up as rosetted, crinkled new leaves, so lock it into the routine.
Pruning
Prune in late winter while the tree sleeps. Train a young tree to a single central leader and cut out crossing, dead, or weak limbs; a mature tree asks for little beyond clearing deadwood.
Repotting
Field-grown pecans skip repotting, and a deep taproot makes them a bear to move. Shift young nursery stock just once while dormant, and keep tabs on container trees for circling roots, stalled top growth, or soil that dries out fast.
Size & spacing
Gear up for a giant. A pecan climbs to 66 to 131 feet (20 to 40 m) tall with a spread of 39 to 75 feet (12 to 23 m), so plant it well back from buildings and lines and give it wide berth from other trees.
When to plant
Pecans go into the ground while they sleep. Plant young dormant trees in late winter to early spring once the worst freezes clear out, and the catkins burst forth in spring. The nuts take their sweet time, ripening on the tree from October into November.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: late winter to early spring while dormant, after the worst freezes
- Harvest: wind-pollinated catkins and flowers in spring; nuts ripen and are harvested October through November
Hardiness
USDA hardiness zones: 6–9
Temperature: down to -23°C
Troubleshooting
Nearly every pecan hiccup traces to wet-weather disease, a hungry tree, or sap-feeding insects. Spot the signs early on the leaves and swelling nuts and you can pounce before a season's crop slips away. Match what shows up below, then move while it still turns the tide.
Black sunken spots on leaves and shucks as young nuts drop
Meet pecan scab, a fungus that charges ahead in warm, humid weather and topples more crops in the wet Southeast than any other problem. Get ahead of it: run a protective fungicide schedule right through the season, open the canopy with smart spacing and pruning so leaves dry fast, and plant scab-resistant cultivars wherever the summers turn steamy. Do that and the crop pulls through.
Fix:
- Apply recommended fungicides on a protective schedule during the growing season
- Improve air movement by proper spacing and pruning
- Plant scab-resistant cultivars in humid regions
Crinkled, yellow-mottled new leaves crowded into rosettes
Crinkled, bronzed new growth bunched at the tips means the tree is chasing zinc, a shortfall pecans hit fast on sandy or high-pH soils. Jump on it with a foliar zinc spray over the fresh spring growth, then fine-tune the soil to match a test. Keep the soil near pH 6 to 6.5 and the roots start grabbing zinc on their own, and the new leaves come back full and flat.
Fix:
- Apply foliar zinc sprays to new growth in spring
- Correct soil zinc per soil test recommendations
Sticky leaves, black sooty mold, and leaves dropping early
That sticky sheen flags pecan aphids, which cluster on the leaf undersides and rain honeydew below until sooty mold blackens the lot. Rally the cavalry first: lady beetles and lacewings mop these up in most seasons, so save a targeted insecticide for the rare blow-up that threatens to strip the leaves. Ease back on nitrogen too, since the soft new growth it pushes is exactly what draws the aphids in.
Fix:
- Encourage natural predators such as lady beetles and lacewings
- Use targeted insecticides only when populations are damaging
Toxicity
Pecan kernels are a safe, well-loved food for people, and the tree itself runs fairly low risk. The catch is moldy fallen nuts, which can pack tremor-causing mycotoxins, plus the rich fat of whole nuts that upsets a pet's stomach. Rake up the drops and keep pets from scavenging, and the worry all but clears out.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
Let a cat nibble a fallen nut and the rich fat may leave its stomach a bit off. The one to head off is a moldy nut, whose mycotoxins can spark tremors or something worse.
Dogs Mild
Dogs dive for windfall nuts faster than any other pet, and that heavy fat can kick off vomiting or diarrhea. Stay alert for trembling or a wobbly gait, because those flag a moldy nut and a trip to the vet.
Horses Mild
Fresh nuts and leaves barely register with a horse, but moldy fallen nuts that slip into feed or pasture can pack the same tremor-inducing mycotoxins. Sweep the ground clear under the tree wherever horses graze.
Rabbits Mild
A rabbit's gut runs on greens, not fatty nuts, so even one fresh kernel can throw its digestion off. Keep pecans off the treat list and stash fallen, moldy nuts well out of reach.
Livestock Mild
Cattle, goats, and sheep grazing under the canopy can scoop up moldy windfall nuts, and the mold toxins, not the tree, are what to guard against. Rake the drops off any grazed ground.
Birds Mild
Backyard hens peck split nuts off the ground with no trouble at all, but moldy ones carry that same mycotoxin risk. Clear the drops so nothing rotten ends up eaten.
People Safe
Dig into ripe pecan kernels freely, since they are a well-loved and perfectly safe food. Just steer clear of any nuts gone moldy on the ground, and keep those away from pets.
Keep fallen nuts raked up so pets cannot scavenge moldy ones; the fresh kernels are not considered highly toxic but the high fat content and obstruction risk make them unsuitable as pet treats.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Pecan cultivars sort out by when they release pollen and how tough they stand against scab. These names come up again and again, and pairing two of them is what packs the crop.
Pawnee
A Type I cultivar that races to ripen early, which makes it a winning pick at the northern edge of pecan country.
Desirable
A Type II cultivar prized for big, top-quality nuts, though it takes scab hard in humid regions.
Elliott
A Type II cultivar planted all across the humid Southeast because it shrugs off scab so well.
Stuart
An old and much-planted Type II cultivar that keeps cropping steadily and holds up fairly well to scab.
Companions
Plant near
Crimson clover or other legume cover crops: Cover crops between rows add nitrogen, reduce erosion, and support beneficial insects in orchards.
Keep apart
Tomato: Pecan produces juglone (milder than black walnut), which can stress juglone-sensitive plants like tomato grown directly beneath the canopy.
How to propagate
Forget growing a named pecan from a planted nut. Cultivars get grafted onto seedling rootstock, and seed itself is raised mainly to build that rootstock.
GraftingDemanding
Late winter to spring for whip and tongue or patch budding in summer · Named cultivars graft onto seedling rootstock and begin bearing in roughly 4 to 8 years
Named pecans won't come true from a nut, so growers graft or bud them onto vigorous seedling rootstock and keep the variety locked in. Run whip and tongue grafts from late winter into spring, or patch bud through summer, and a grafted tree kicks into bearing in roughly 4 to 8 years.
SeedModerate
Stratify nuts over winter and sow in spring · Seedlings used mainly as rootstock; seedling-grown trees are variable and bear after many years
Sow seed to raise rootstock, not to clone a named cultivar. Chill the nuts through winter and sow them come spring, but count on seedling trees to turn out variable and to make you wait many years for nuts.
Myths
A single pecan tree will reliably crop on its own.
It rarely delivers. Pecans are wind-pollinated and stagger their timing, so a Type I tree fires off its pollen before its own flowers open, while a Type II tree flips that order. Plant both types close together and cross-pollination drives the yield way past whatever one lonely tree can pull off.
All pecans are dangerously poisonous to dogs.
Shake off that fear. Fresh kernels aren't highly toxic, though a whole nut can upset a stomach or cause a blockage and carries plenty of fat. The real danger is moldy nuts, which can hold tremor-causing mycotoxins, so the move is simply to rake up the drops instead of dreading the tree.