Koelreuteria paniculata survives well in Zone 5 as long as winters aren't too severe in the first year after planting. Late summer and fall fruit development is also interesting as the flowers are replaced by yellowish brown, bladder-like pods an inch or so in diameter. As they fully ripen, the fruit turns a rich brown and persists well into the fall. Trees can reach heights of 25 to 30 feet with an equal spread. Sophora japonica flowers in mid-August and is hardy into Zone 4.
Flowers are yellowish-white born in upright pyramidal clusters all over the surface of the tree.
The fruit is an elongated greenish pod containing several bean-sized seeds. Twig color is a bright green which adds a degree of life to the winter landscape. Pagoda Tree can get to be well over 50 feet tall with a spread of 35 to 40 or more feet, so it does need considerable space in a planting. This small tree is listed as hardy into Zone 5, but is often injured by very severe winters in some parts of the zone. It is a member of the camellia family and its single white blossoms have somewhat cupped petals.