Catalpa bignonioides seeds - Indian bean tree

Catalpa bignonioides, common catalpa or broad-leaved catalpa, is a firm favourite in gardens. It is a handsome shade tree, with ornamental foliage, flowering and fruit. Its large heart-shaped leaves, white flowers speckled with yellow and purple, and long hanging pods give it an almost exotic look, although it is very hardy and easy to grow. 
Growing from seed allows you to watch several catalpas grow, well suited to your plot. They grow quickly, and in 6 or 7 years you will have specimens capable of providing welcome shade.

This tree belongs to the Bignoniaceae family, the same as climbing bignonias. The species Catalpa bignonioides is the currently accepted name; several older names are attached to it, including Bignonia catalpa, Catalpa syringaefolia, Catalpa arborea or Catalpa catalpa. Native to the south-eastern United States, where it is found along rivers and at the edge of deciduous-leaved forests. Introduced to Europe in the 18th century, it has become a common ornamental tree in parks and gardens.
It is a medium to large deciduous tree, developing a fairly short trunk and a broad, rounded, very spreading crown. At maturity, it reaches 10 to 15m tall with an 8 to 12m spread; it reaches 5 to 6m tall in about ten years. The simple, entire, heart-shaped leaves measure 15 to 25cm long and 10 to 20cm wide. They are grouped in twos or threes, are light green, smooth on the upper surface, more downy underneath, and give off a strong smell when crushed. They appear late in spring and fall fairly early in autumn. In early summer, the catalpa bears large upright panicles of bell-shaped flowers, creamy white spotted with yellow and purple inside, visited by insects. Each flower measures 3 to 4cm long. They are followed by long slender, cylindrical, pendulous capsules, sometimes exceeding 30cm in length, which persist throughout winter. The winged seeds are dispersed by the wind.
The root system is vigorous, rather shallow and spreading, with thick fleshy roots. They anchor the tree and make it useful for stabilising certain soils, but should not be planted too close to a wall, pipe or terrace.

In the garden, broad-leaved catalpa proves far less demanding than its appearance suggests. It grows in most garden soils, even heavy or clayey ones, provided they do not remain waterlogged permanently. Growing from seed is the most economical method of obtaining this tree. The drawback is the patience required: from sowing, allow about 3 to 4 years for a young tree of 2 to 3m, then 8 to 12 years for a fine, well-formed specimen.

It is first and foremost a shade tree: plant it near a terrace, at the edge of a lawn or close to a play area, giving it room to spread its crown. You can pair it with a lighter tree such as Heptacodium miconioides, adorned with red bracts in late summer, or with a Parrotia persica 'Vanessa', for its superb autumn foliage. The catalpa plays the role of the great leafy parasol, while the other shrubs dress its base.