Southern catalpa

Catalpa bignonioides · Southern catalpa (EN) · Trompetenbaum (DE)

The southern catalpa (Catalpa bignonioides), known as the Indian bean tree, is a striking tree with enormous, heart-shaped leaves, white flowers in panicles and long, bean-like pods that hang from the branches all winter.

Full sun/Partial shade Medium watering USDA 5a–9a
Watering calculator

In short

  • Heart-shaped leaves up to 30 cm — among the largest of the trees grown in Poland.
  • Comes into leaf very late, in May or June — in spring it looks dead, though it is healthy.
  • White flowers in panicles in June and July, then pods up to 40 cm hanging through the winter.
  • The branches are brittle — plant in a spot sheltered from wind, away from the terrace and drive.
  • Very good for bees; non-toxic, and therefore safe in a garden with children and animals.

Botanical data

Family
Bignoniaceae (Bignoniaceae)
Height
8–15 m
Width
8–12 m
Habit
Spreading
Growth rate
Fast
Position
Full sun, Partial shade
Soil
Humus-rich, Loamy, Sandy
pH reaction
pH 5.5–7.5
Moisture
Moderate, Moist
Bloom
June–July
Hardiness
USDA 5a–9a
Propagation
From seed, From cuttings

Characteristics

A tree with a broad, domed, fairly low-set crown and thick, stiff shoots. The leaves are set in opposite pairs or in whorls of three, heart-shaped, up to 30 cm in length and width, and give off an unpleasant smell when crushed. The flowers are bell-shaped, white, spotted yellow and purple in the throat, gathered into large, erect panicles. The fruit is a thin, cylindrical pod 20–40 cm long, turning brown in autumn and hanging from the leafless branches all winter.

Growing and care

Watering

The enormous leaves transpire heavily — in hot weather young trees wilt visibly and need generous watering. Mature specimens cope on their own.

In summer every ~7 days · drought tolerance: Medium

Fertilizing

Moderately — excess nitrogen produces long, soft growth that is even more prone to breaking.

once a year in spring, for young trees · kompost, nawóz wieloskładnikowy

Planting

A warm, sunny and above all WIND-SHELTERED position — in a draught the brittle branches and huge leaves break off easily. Soil fertile and well-drained.

Timing: April–May (safer than autumn, as young catalpas are sensitive to frost) · spacing 800–1000 cm

Pruning calendar

Pruning group: Deciduous trees — pruning during dormancy

Why then: In leafless dormancy the whole framework of the crown is visible, and the tree is not in full growth — wounds heal more calmly, and the risk of spreading diseases is lower. This is the safest time to prune these trees.

What and how to cut

Prune from late autumn to early spring, on frost-free days. Remove dead, diseased, damaged and crossing shoots, along with competing leaders, leaving one main leader. Prune sparingly. Make the cut just beyond the swollen branch ring (collar) at the base of the branch — not flush with the trunk and without leaving a stub; a wound like this heals over best.

In early spring, before the buds open (March).

What not to do

Do not remove large limbs without a clear need, and for thick, tall trees leave the pruning to arborists. Do not prune in early spring when the sap starts to rise, or during frost. In a single season, do not remove more than roughly a quarter of the crown.

Companion plants

Good companions

Spring squills and crocuses under the crownPractical observation

The catalpa comes into leaf only in May or June, so it is bright beneath its crown all spring — the geophytes have time to flower and rebuild their bulbs.

Siebold's plantain lilyPractical observation

It tolerates the shade cast by the catalpa's enormous leaves, and their large blades create a coherent composition of coarse texture.

Bad companions

Terraces, drives, swimming pools and parking spacesPractical observation

The large falling leaves, spent flowers and long pods make a great deal of mess, and the brittle branches break in stronger winds.

The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.

Diseases and pests

Verticillium wilt

The first symptom is a sudden wilting and drying of leaves on individual branches or on one side of the crown, while the rest of the plant appears healthy. A cross-section of an infected shoot reveals a brownish or greenish discolouration of the wood — the vascular bundles clogged by the fungus, which can no longer conduct water. The disease progresses over successive years, affecting an ever-larger part of the crown and leading to the gradual death of the plant. Maples (especially Japanese maple), catalpa and many other trees, shrubs and perennials are particularly susceptible. The disease takes two forms: an 'acute' form, in which a branch or the whole plant dies rapidly within a few weeks, and a 'chronic' form — a slow decline spread over several seasons, with smaller, paler leaves, marginal scorching of the blades (resembling sunburn) and premature autumn colouring on infected shoots. The sectoral, one-sided distribution of symptoms is the hallmark of Verticillium wilt above all on woody plants — the part of the crown supplied by the clogged vessels dies off. The discolouration of the wood is best seen just under the bark as longitudinal streaks, and in cross-section as an interrupted ring; in maples it is often olive-green. Symptoms intensify in heat and during drought, when the demand for water exceeds the capacity of the damaged bundles. On herbaceous plants (dahlia, aster, chrysanthemum, tomato, potato, strawberry) one observes wilting and yellowing of the lower leaves, stunting and one-sided (half-blade) yellowing of the leaf — on these species, however, the symptom picture alone is unreliable for differentiation, because one-sided yellowing may also be caused by Fusarium wilt. The vascular discolouration by itself is not conclusive — a definitive diagnosis requires laboratory isolation of the pathogen.

Toxicity

For whomLevelNotes
Humans None The catalpa is not counted among toxic plants; the pods and seeds are inedible but are not regarded as toxic.
Dogs None
Cats None

History and origin

Brought to Europe at the beginning of the 19th century and quickly appreciated for its exotic, almost tropical appearance — it was planted in landscape parks and urban avenues. In the USA the species was also grown with a view to rearing caterpillars used as fishing bait and for its durable, rot-resistant timber for fence posts.

Uses

For parks, large gardens and urban plantings as a specimen on a lawn, where the whole silhouette and the pods can be seen. It tolerates air pollution. For smaller gardens the cultivar Nana is suitable, grafted on a stem and forming a compact, spherical crown without flowers — planted mainly by entrances and in rows along paths.

Trivia

  • The name cigar tree comes from the pods, which in shape and colour resemble cigars hanging from the branches.
  • The catalpa starts into growth as one of the last trees in the garden and finishes as one of the first — its leaves blacken and fall after the first sharper frost, practically without any autumn colour.

Frequently asked questions

My catalpa has no leaves in May — has it died?

Almost certainly not. The catalpa is one of the last trees to come into leaf in our climate — the buds usually stir in the second half of May, and sometimes only in June, when the rest of the garden is already fully green. This is the most common cause of panic among owners. Before you declare the tree dead, scrape a little bark off a young shoot with your fingernail: if it is green and moist underneath, the tree is alive and simply waiting for warmth.

Is the catalpa suitable for a small garden?

The species itself rather not — it reaches 8–15 m in height with a similar crown width, drops a lot of litter in the form of leaves, flowers and pods, and its brittle branches break in the wind. For small gardens the cultivar Nana is planted, grafted on a stem at about 2 m: it forms a compact ball 2–3 m across and practically does not flower, so it sets no pods either.

Are catalpa pods and seeds toxic?

No. The catalpa is not counted among toxic plants, either for people or for dogs and cats — the pods are simply inedible and dry. It is one of the few striking, exotic-looking plants that can be planted without concern in a garden with small children. Crushed leaves, on the other hand, have a distinctly unpleasant smell.

Sources

Edited by:Redakcja Atlas-Flora. Updated: 7/16/2026.

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