18 Jul

Tree of the month: The Indian Bean Tree

This month we take a look at the Indian Bean Tree! Also commonly known as the Southern Catalpa or the Cigar Tree, this luscious specimen is widely grown as an ornamental tree in stately parks as well as private gardens…

The Indian Bean Tree (Catalpa bignonioides) has the distinction of bearing some of the showiest flowers of all the American native trees. Contrary to what its common name might suggest, the tree does not originate in India, and it does not grow beans. Nevertheless, the large heart-shaped leaves grow to 20–30 cm long and 15–20 cm broad, making it a bushy, full-looking addition to any garden. It’s a wonderful specimen to observe throughout the year, with distinct changes to look forward to with the coming of each season.

The medium-sized deciduous tree grows to 15–18 metres (49–59 ft) tall in good conditions, with a trunk up to 1 metre (3 ft 3 in) diameter that features a brown to grey bark with hard plates and ridges. The short thick trunk supports long and straggling branches which form a broad and irregular head, making it a very popular parkland tree.

The bright green, heart-shaped leaves emerge suddenly in late June, and as they are full-grown before the flower clusters open, they put on a vibrant display in their own right. They also secrete nectar, a rather unusual characteristic for leaves, by means of groups of tiny glands in the axils of the primary veins.

The main event during the year is the fabulous bloom of flowers – which are small and white with yellow and purple flecks. They appear in July and can be so numerous as to obscure the leaves of the tree altogether.

Magic beans

The Indian Bean tree continues to put on a show throughout the year by producing long, slim, and cylindrical seed pods that look rather like beans and can grow up to 16 inches in length. These pods hang from the tree all winter, splitting to release many silvery-grey, winged seeds.

Cherokee origins

Catalpa bignonioides is a member of the Catalpa species and hails from the south-eastern parts of the United States in the regions of Alabama, Florida, Georgia, Louisiana, and Mississippi.
This US native was first observed by European botanists in the fields of the Cherokee Native American tribes, who called it Catawba. However, it seems the Latin transcription of the name was just a mistake, with Catawba misspelt as Catalpa by a careless botanist!

Grow your own

If you fall for this hardy tree, like so many do, it can be fairly easy to introduce into your own garden. The 3.7m-high ‘Nana’ would be a good choice for those with smaller gardens. The Indian Bean can be raised from seeds which germinate early in the first season and it also multiplies readily from softwood cuttings.

Saplings prefer to grow in a moist but well-drained, fertile soil in a sunny position, although it will also tolerate heavy clay soil. It’ll do better with a little bit of shelter from strong winds as these may damage the large leaves and also protection from late spring frosts when it’s young.

As it never forms a terminal bud, the last bit of late summer stem growth is almost always damaged by winter frosts, which leads to its multi-branched habit. The tree is mostly free from fungal diseases and has few insect enemies. The best time to plant is October to March.

Fan favourite

Introduced to Europe in 1726, the Indian Bean tree has become a favourite of both prestigious garden designers and green-fingered homeowners alike. Having been given the Award of Garden Merit by the Royal Horticultural Society (RHS), along with its gold-leafed C. bignonioides ‘Aurea’ and purple-leafed hybrid C. × erubescens ‘Purpurea’ siblings, it’s no stranger to being recognised for its dazzling brilliance.

The award marks the quality of the tree’s performance under UK growing conditions, so it should come as no surprise that this US native is a UK favourite. Indeed, even here at Westbury Windows & Joinery – we’ve been won over by the Indian Bean’s readiness to put on a fabulous spectacle and visitors to our show room often remark at the beautiful specimen we have growing in the courtyard. Perhaps it’s time for you to discover this celebrated star of the horticultural stage!