‘Blue Moon’ and Other Cold Climate Wisteria Hardy to Zones 3 & 4

Gardeners in garden zones 3 and 4 are often reluctant to plant wisteria, but they can and with proven results. Kentucky wisteria, W. macrostachya, has some named cultivars that are quite hardy, even to zone 3, depending on the garden’s micro climate. The hardiest are ‘Blue Moon’ and ‘Aunt Dee’.

Flowers on New Growth

With the vigorous Asian wisteria, like the Japanese, W. floribunda, and the Chinese, W. sinensis, the flowers are born on the previous year’s growth, but with W. macrostachya ‘Blue Moon’ and ‘Aunt Dee’, the flower racemes emerge from new growth. This makes the varieties ideal in the north, because winter die-back can occur. The vine will grow even if the plant has died back to the roots. New growth can be slower to emerge than other vines and shrubs in the garden, so gardeners should not assume it’s dead.

Planting and Culture of Hardy Wisteria

These hardy wisteria vines are still quite vigorous, but easier to manage than the Asian wisterias. Choose a location in full sun, preferably away from other plants like trees that the vine could eventually strangle if left unchecked. Amend the soil with humus rich material. The planting bed should be well-drained, but moist.

Unlike most wisteria, ‘Blue Moon’ is expected to produce flowers by the third year, if not the second. It does have similar growing habits to the Asian wisterias, in that it will send out runners or suckers just below or at ground level. If these aren’t pruned out, the vine could be all foliage and no flora. Prune only after the flowers are spent.

‘Blue Moon’ with its lavender blue flowers and ‘Aunt Dee’ with its lavender lilac colored flowers can grow to 30′ with up to 12″ long racemes in June – a lovely plant to follow the lilacs in the garden, and they will repeat once or twice over the summer. Their scent is known to be sweet. It’s important to note that ‘Blue Moon’ has shown to have less winter die-back than ‘Aunt Dee’.

Other Named Cultivars of Hardy Wisteria

Other named cultivars of hardy Kentucky W. macrostachya, inlcude ‘Claire Mack’, and ‘Lawrence’. They will flower on new growth, rather than the previous year’s growth, but they are known to have a higher degree of winter die-back.

Gardeners in colder zones could also try the American wisteria W. frutescens, ‘Amethyst Falls’, which is known to survive to garden Zone 4.

Wisteria Needs Strong Supports

Wisteria needs strong supports and space. It can be grown against the wall of a house, but it doesn’t have suckers. It needs to be tied into to something strong, because as it ages, the trunks and stems can become quite thick and heavy which can cause damage to structures. The best support is a sturdy arbor away from buildings and trees.

With good garden skills and proper care and pruning, the hardy wisterias can offer the romance of traditional English gardens, lush with vertical vines and drooping flowers.

Reference

• Ohio State University, Horticulture and Crop Science, “Growing Wisteria”