Tree · Bignoniaceae
Northern Catalpa
Catalpa speciosa
A tough native shade tree that's covered in showy white flowers and grows fast just about anywhere.
Full sun
Every 7–21 days
USDA 4–8
40–70 ft · 12.2–21.3 m
Overview
Want fast shade without a lot of fuss? Northern catalpa is hard to beat. Every late spring it's smothered in showy white flowers that look like little orchids, and come fall it's hung with long, skinny pods, which is how it picked up names like cigar tree and Indian bean tree. The leaves are big and heart-shaped, and that's both the pretty part and the part you'll be raking.
What really makes it stand out is how easy it is to please. It's fine in wet ground or dry, fine in clay, poor soil, or city pollution, and it just keeps growing through a swing from -29°F to 100°F (-34°C to 38°C). That toughness, plus how fast it grows, is why it shows up in the rough spots where pickier trees would throw in the towel.
There's a catch, of course. It makes a mess of big leaves, old flowers, and long pods, and the brittle branches snap in wind and ice. So give it room away from patios and walkways, prune it while it's young so it builds a solid frame, and it'll hand you decades of quick shade for the trouble.
Care
The short version: full sun to part shade and pretty much any soil, wet or dry. Once it's settled it hardly ever wants feeding or extra water, so really the main thing is pruning it young for good structure and putting it somewhere falling limbs and litter won't bug anybody.
Light
Catalpa loves full sun, but it'll take part shade without complaint. More sun means more flowers and a fuller, sturdier crown, while a shadier spot still grows you a perfectly healthy tree, so don't sweat it if the light isn't ideal.
Water
Once it's established, this tree shrugs off both seasonal flooding and drought, so you barely have to water it. Young trees are the exception, though, and they want steady moisture through their first year or two while the roots dig in. Just let the top half of the soil dry out between waterings.
Soil
Honestly, few trees are this laid-back about soil. Catalpa would love a moist, fertile loam with some organic matter, but it's just as happy in clay, soggy low spots, dry poor ground, or rough city conditions.
Temperature
This one's both cold-hardy and heat-tough, living across USDA zones 4 to 8 and riding out anything from -29°F to 100°F (-34°C to 38°C). Once it's in the ground, temperature is basically off your list of things to worry about.
Humidity
Regular outdoor humidity suits it just fine, so there's no number to chase here. What matters more is good air movement, since open airflow keeps the leaf-spot and mildew fungi from settling in.
Feeding
This easygoing native hardly ever needs feeding. If growth is looking weak, one balanced, general-purpose tree fertilizer in spring does the job, and most years you can skip it altogether.
Pruning
Prune in late winter to early spring to clear out dead, weak, or crossing branches and to build a strong central leader. The wood's brittle and breaks easy, so a little early shaping really pays off over the tree's whole life.
Repotting
Catalpa's a landscape tree, not a houseplant, so repotting rarely comes up. If you're keeping a young one in a pot for a while, just bump it up a size when roots start circling inside, poke out the drainage holes, or water runs straight through.
Size & spacing
This is a big tree, hitting 40 to 70 feet (12 to 21 meters) tall and spreading 20 to 50 feet (6 to 15 meters) across. Give it plenty of open room, well clear of buildings, walkways, and power lines.
When to plant
Catalpa isn't picky about when it goes in. Plant it in spring once the last frost is behind you, or wait for fall, and then keep an eye out for the white flower panicles in May and June, with those long pods filling in behind them all summer.
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; seed needs no special pretreatment.
- Plant: Spring after the last frost, or in fall.
- Harvest: Showy white orchid-like flower panicles in late spring to early summer (May to June), followed by long bean-like seed pods.
Hardiness
USDA hardiness zones: 4–8
Temperature: down to -34°C
Troubleshooting
Here's the good news: catalpa is a tough tree, and most of what bothers it is more of an eyesore than a real threat. The one to take seriously is verticillium wilt, because there's no cure for it, so it's worth telling them apart. Match what you're seeing below before you grab any treatment.
Wilting that comes on fast, often just one side
This one's verticillium wilt, a soilborne fungus that clogs the wood from the inside, and there's no chemical cure. Want to confirm it? Cut a wilting branch and look for brown or greenish streaks under the bark. Prune out the affected limbs, keep the tree well watered so it stays vigorous, and if it dies, don't replant a susceptible species in that same spot.
Fix:
- Prune out and dispose of affected branches
- Keep the tree vigorous with proper watering, as there is no chemical cure
- Avoid replanting susceptible species in the same soil if a tree dies
Busted branches and ripped-up leaves after bad weather
Catalpa wood is naturally brittle, so wind, ice, and hail break limbs and shred those big leaves. After a storm, look for snapped or hanging branches and prune them off cleanly. Train young trees to a strong central leader early, and plant where a falling limb won't come down on a patio or walk.
Fix:
- Prune cleanly to remove broken or hanging limbs
- Develop a strong central leader and good branch structure with early structural pruning
Big holes in the leaves, or hardly a leaf left
That's the catalpa sphinx caterpillar, usually called the catalpa worm, and it eats nothing but catalpa. They pile on together and can strip a tree in mid to late summer, but here's the thing: the tree just re-leafs and shrugs it off. Pick them off a small tree if you want, or leave them alone, since plenty of anglers love them as fish bait.
Fix:
- Handpick caterpillars from small trees, or simply tolerate them since trees easily re-leaf
- Harvest them as fish bait, for which catalpa worms are prized
- Apply a labeled caterpillar control such as Bt or a recommended insecticide only for heavy infestations on small or young trees
That white dust or dark spots showing up on leaves
Those are powdery mildew and leaf spot fungi, sometimes with a bit of twig blight that kills off small shoots. Bad mildew can yellow the leaves and drop them early, but it stays cosmetic and rarely needs a fungicide. Just rake up and toss the fallen leaves and open up the canopy for better airflow.
Fix:
- Rake and dispose of fallen infected leaves
- Improve air circulation
- These foliar problems are largely cosmetic and rarely require fungicide
Toxicity
Got pets? Good news, because catalpa is not toxic. It never landed on the ASPCA poison-plant lists, and those long bean-like pods aren't something to eat, but they're not a poisoning risk either. The only thing to watch is the foliage, which can leave sensitive skin a little itchy, so throw on gloves for a big cleanup.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Catalpa's not on the ASPCA toxic list, so if a curious cat bats at a fallen pod, there's nothing to worry about.
Dogs Safe
No poisoning risk here. A dog that chews a stray pod might get a mild stomachache from the bulk, but the tree itself isn't toxic.
Horses Safe
Catalpa has no known toxin for horses and isn't on any poison-plant lists, so they're fine around it.
Rabbits Safe
There's nothing toxic to rabbits in the leaves or pods, so a nibbled leaf is no big deal.
Livestock Safe
Cattle, goats, and sheep can graze around a catalpa just fine, since the tree isn't a recognized poisoning hazard.
Birds Safe
Birds don't come to any harm from the foliage or the long pods.
People Safe
The tree's safe to be around, though the pods aren't for eating and the foliage can leave sensitive skin a little itchy, so wear gloves for a big cleanup.
The long seed pods and large leaves create heavy litter, and the foliage can cause minor contact dermatitis in sensitive people, so wear gloves when handling.
Varieties
A few different catalpas turn up in yards and along streets, from the big northern and southern species to a couple grown just for their shape or color. Here are the ones worth knowing by name.
Catalpa speciosa (Northern catalpa)
This is the bigger, hardier species, growing tall and upright with green-scented leaves, and it shrugs off the cold right down through zone 4.
Catalpa bignonioides (Southern catalpa)
A smaller, rounder tree with fetid-scented foliage and flowers spotted more heavily in purple that open a touch later in the season.
Catalpa bignonioides 'Nana' (Umbrella catalpa)
A dwarf, non-flowering form that's grafted onto a standard trunk, so it grows into a dense, rounded umbrella of a head.
Catalpa bignonioides 'Aurea'
A golden-leaved pick that's grown for its bright yellow to yellow-green foliage.
How to propagate
Want more catalpas? That's easy. You can sow the seed straight out of the pods, or take a cutting off a tree you've already got going.
SeedEasy
Collect seed from the long bean-like pods in fall and sow in late winter to spring. · 1 to 2 seasons
Seed is the easy way to go. Grab it from the long pods in fall and sow from late winter into spring, and you don't need to soak or chill it first. It sprouts without much fuss, and because the tree's so fast, it fills out to landscape size within a season or two.
Stem cuttingsModerate
Softwood cuttings in early summer or hardwood cuttings in the dormant season. · 1 season to root
You can also start catalpa from cuttings, taking softwood in early summer or hardwood while the tree's dormant, and they take about a season to root. Root cuttings work too. Named forms like 'Nana' are usually grafted instead of cut, since they won't come true on their own roots.
Myths
Those catalpa worms will eat every last leaf and take the whole tree down.
Sure, the catalpa sphinx caterpillar can strip a tree bare, but it grows its leaves right back and comes through fine, even after the same thing happens several years running. The defoliation looks alarming but does no lasting harm, so you rarely need to lift a finger.
Those bean-shaped pods are dangerous if a pet eats one.
Nope. Catalpa never made the ASPCA toxic-plant lists, so it counts as non-toxic. The long pods are inedible but not a poisoning hazard for cats or dogs.