Catalpa bignonioides Aurea

Catalpa bignonioides Aurea is a small, slow-growing tree, of moderate proportions, selected for its extremely decorative and luminous, golden spring foliage. The young purplish leaves quickly turn golden yellow, becoming soft green in the summer, then deep yellow in autumn. Unpruned, this Catalpa produces white flowering panicles in spring, followed by long pendant pod-shaped fruits. It provides very pleasant, deep shade in a summer garden. Pruning it to the ground provides spectacular results for this variety, producing a strong visual impact in the garden, unfortunately at the expense of flowers.

Catalpa bignonioides Aurea, also known as the Indian Bean Tree, is a deciduous tree from the Bignoniaceae family: it's a cousin of beautiful climbers like Campsis, Bignonia, Podranea, and other Tecomaria. Native to the southeastern United States, it was introduced to Europe in 1726. It is a light-loving species that appreciates rather moist soils, tolerates alkaline, and is highly resilient to urban pollution.

The cultivar 'Aurea' was selected before 1877. It is slow-growing and fairly compact.  If it is not pruned, it will naturally grow into a spreading, parasol shape on a short trunk. This small tree will measure between 5 and 7 m (16 - 23 ft) in height and develop a crown of 4 to 5 m (13 - 16ft) by the age of 10. Eventually, it will reach a height and spread of about 8 m (26ft). Its grey-brown, lightly ridged bark peels off in small patches over time. Its branches are brittle, so it needs to be protected from strong winds. Its foliage is deciduous, appearing late in spring and quickly falling in the autumn. The leaf buds are purplish copper when they begin to emerge. Its large leaves have an elongated heart shape, golden-yellow in spring, green-yellow in summer, and then yellow again in autumn. Flowering occurs in May, at the tips of the branches in the form of panicles of bell-shaped flowers with frilly edges. The outer part of the flowers is white, while the inside is purple and golden yellow. The nectar-rich flowers are pollinated by insects and produce pendant pods, resembling large beans. The Catalpa's shallow root system dislikes drought and makes it susceptible to strong winds. The plant will benefit from severe pruning every 2 or 3 years to keep it dense. It can be pruned into a central leader or coppiced depending on the available space.

Catalpa 'Aurea' is suitable for both large and small gardens, but it is not recommended for excessively windy locations. It can be planted as a specimen in a city garden, in the centre of a well-manicured bed of box, creeping Japanese euonymus, or Lonicera nitida. Its shallow root system draws up a lot of water in summer, so it is best to choose plants that require little water or plant beyond the edge of the canopy (the dripline). For an alternative natural parasol, plant Robinia pseudoacacia 'Umbraculifera', which is better suited to dry soils. Gardeners looking for an exotic touch could possibly combine it with the Golden Shadow Paper Mulberry, Broussonettia papyrifera.