Tree · Bignoniaceae
Northern Catalpa
Catalpa speciosa
A tough native shade tree that throws showy white flowers and grows fast almost anywhere.
Full sun
Every 7–21 days
USDA 4–8
40–70 ft · 12.2–21.3 m
Overview
Northern catalpa is a big, fast-growing native that earns its keep as a shade tree. In late spring it covers itself in showy white flowers shaped like little orchids, and by fall it hangs long, slender seed pods that give it nicknames like cigar tree and Indian bean tree. The heart-shaped leaves run large, which is part of its charm and part of the cleanup.
What sets it apart is how little it asks. It takes wet ground and dry ground, clay, poor soil, city pollution, and a swing from -29°F to 100°F (-34°C to 38°C), and it keeps growing through all of it. That toughness, plus its speed, is why it turns up in tough planting spots where fussier trees give up.
The trade-off is the mess and the wood. Catalpa drops big leaves, spent flowers, and long pods, and its brittle branches snap in wind and ice. Give it room away from patios and walks, prune it young for a sound frame, and it rewards you with decades of fast shade.
Care
The short version: full sun to part shade and just about any soil, wet or dry. It rarely needs feeding or extra water once it's settled, so the main job is pruning young for strong structure and siting it where falling limbs and litter won't be a nuisance.
Light
Catalpa does best in full sun but takes part shade in stride. More sun means heavier flowering and a denser, sturdier crown, while a shadier spot still grows a healthy tree.
Water
Once established, this tree handles both seasonal flooding and drought, so it rarely needs watering. Young trees are the exception and want regular moisture through their first year or two while the roots reach down. Let the top half of the soil dry between drinks.
Soil
Few trees are less picky about soil. Catalpa prefers a moist, fertile loam with some organic matter but tolerates clay, soggy low spots, dry poor ground, and rough urban conditions without complaint.
Temperature
This is a cold-hardy, heat-tough tree that lives across USDA zones 4 to 8 and rides out a range from -29°F to 100°F (-34°C to 38°C). Once it's in the ground, temperature is rarely something you have to manage.
Humidity
Ordinary outdoor humidity suits it fine, so there's no number to chase. Good air movement matters more, since open airflow keeps the leaf-spot and mildew fungi from getting a foothold.
Feeding
This adaptable native rarely needs feeding at all. If growth looks weak, a single balanced, general-purpose tree fertilizer in spring is plenty, and most years you can skip it entirely.
Pruning
Prune in late winter to early spring to take out dead, weak, or crossing branches and to build a strong central leader. The wood is brittle and breaks easily, so early structural pruning pays off for the life of the tree.
Repotting
Catalpa is a landscape tree, not a container plant, so repotting rarely comes up. If you do hold a young one in a pot, move it up when roots circle the inside, push through the drainage holes, or water runs straight through.
Size & spacing
This is a large tree, reaching 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, walks, and power lines.
When to plant
Catalpa is easy to get going and patient about timing. Plant it in spring once the last frost has passed, or in fall, and look for the white flower panicles in May and June, with the long seed pods forming behind them through 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
Catalpa is a hardy tree, and most of what troubles it is more cosmetic than serious. The big exception is verticillium wilt, which has no cure, so it pays to know the difference. Match what you see below before you reach for any treatment.
Sudden wilting and dieback, often on one side first
Verticillium wilt is a soilborne fungus that clogs the wood from the inside, and there is no chemical cure. Cut a wilting branch and check for brown or greenish streaks under the bark to confirm it. Prune out the affected limbs, keep the tree well watered to hold its vigor, and don't replant a susceptible species in that spot if the tree dies.
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
Snapped limbs and tattered leaves after a storm
Catalpa wood is naturally brittle, so wind, ice, and hail break limbs and shred the 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 falling limbs won't threaten 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
Leaves chewed away or the whole tree stripped in summer
This is the catalpa sphinx caterpillar, often called the catalpa worm, and it feeds on nothing but catalpa. The caterpillars gang up and can strip a tree in mid to late summer, but the tree re-leafs and shrugs it off. Handpick them from a small tree if you like, or leave them be, since plenty of anglers prize 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
A white powdery film or dark spots on the leaves
These are powdery mildew and leaf spot fungi, sometimes joined by twig blight that kills off small shoots. Bad mildew yellows the leaves and drops them early, but the damage stays cosmetic and rarely calls for a fungicide. Rake up and bin the fallen leaves and open 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
Good news for households with pets: catalpa is not toxic. It never made the ASPCA poison-plant lists, and the long bean-like pods, while inedible, aren't a poisoning hazard. The only real caution is the foliage, which can leave sensitive skin a little itchy, so wear gloves for a big cleanup.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
Catalpa doesn't appear on the ASPCA toxic list, so a curious cat that bats at a fallen pod isn't in danger.
Dogs Safe
No poisoning hazard here. A dog that chews a stray seed pod might get a mild stomach upset from the bulk, but the tree itself is not toxic.
Horses Safe
Catalpa carries no known toxin for horses and isn't on poison-plant lists.
Rabbits Safe
The leaves and pods hold nothing toxic to rabbits, so a nibbled leaf is harmless.
Livestock Safe
Cattle, goats, and sheep can graze around a catalpa without risk, since the tree is not a recognized poisoning hazard.
Birds Safe
Birds come to no harm from the foliage or the long seed pods.
People Safe
The tree is safe to be around, though the pods are inedible 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 catalpas turn up in yards and along streets, from the towering northern and southern species to a couple of selections grown for their shape or color. These are the ones worth knowing by name.
Catalpa speciosa (Northern catalpa)
The larger, hardier species, growing tall and upright with green-scented leaves and shrugging off cold down through zone 4.
Catalpa bignonioides (Southern catalpa)
A smaller, more rounded 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 grafted onto a standard trunk so it grows into a dense, rounded umbrella of a head.
Catalpa bignonioides 'Aurea'
A golden-leaved selection prized for its bright yellow to yellow-green foliage.
How to propagate
Catalpa is happy to multiply, whether you sow the seed straight from its pods or strike a cutting from a tree you already have.
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 simplest route. Gather it from the long pods in fall and sow from late winter into spring, with no soaking or chilling needed first. It sprouts readily, and because the tree grows 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 is dormant, and they take about a season to root. Root cuttings work too. Named forms like 'Nana' are usually grafted rather than struck from cuttings, since they don't come true on their own roots.
Myths
The catalpa worm eats every leaf and kills the tree.
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 do anything about it.
The bean-like pods are poisonous to pets.
Catalpa never made the ASPCA toxic-plant lists and counts as non-toxic. The long pods are inedible but not a poisoning hazard for cats or dogs.