Catalpa bignonioides ‘Nana’

Catalpa bignonioides ‘Nana’ is a top-grafted specimen useful in Melbourne streetscapes where power lines are a problem. This plant will form a tight ball of heart-shaped, rich green foliage in summer. In autumn, the foliage turns a rich, bright yellow and holds for a week on the plant.

Catalpas were widely used in Victorian-period landscapes, imparting a lush appearance. The dwarf form was selected in France in 1850 and was used as shrub mass. Grafting this form on standards has been performed widely since about 1880, and these grafted trees have been prized for their dense form with vivid green appearance.

C. bignonioides ‘Nana’ does not flower often, and is used for its foliage. It is denser than ‘Mop Top’ Robinias, and should be tolerant of a wider range of sites than Ficus microcarpa var. hillii. As it will not be wider than 2 to 3m (with exceptional age and without any pruning), it can be used in extremely restricted areas. With pruning, it should be able to be kept to 1.5m width. Catalpas will grow in full sun, and in Australia, they should be able to be grown with easterly light only with no loss of quality.

This plant is a new opportunity to grow a formal, topiary-like plant in areas where others have not performed.

Typical mature height:

4m (grafted at 2m)

Useful in:

height-restricted areas

Sites for best growth:

streetscapes with good drainage