Wisteria. Even its very name sounds mysterious. If you have ever been to England and visited the castles there, you will have noticed this beautiful vine covering the castle garden walls with its fragrant, lavender blooms draping down from the ancient archways.

It was then I decided I must have some for my own garden.

I soon discovered most wisteria is not a plant reliably hardy to our northern Iowa weather. After further investigation, I found a wisteria cultivar that would grow in zone 4. This cultivar is ‘Aunt Dee’ and I purchased two vines already growing in pots. The vines are quick to grow, but slow to flower, as wisteria has a longer than average juvenile period, taking up to 3 or 4 years to bloom.

The ‘Aunt Dee’ cultivar is a Kentucky wisteria, (Wisteria macrostachys), which can grow to 15-25 feet at maturity with pale lavender blooms, 8-12 inches long. Nothing compares to the beauty and fragrance of a wisteria arbor in full bloom, but patience is needed for these plants to reach maturity.

Last year, I was very excited to have my first wisteria blooms. Though scanty in number, the flowers were beautiful racemes, a horticulture term for these dangling flower clusters packed tight with blooms. I planted each vine on a sturdy arbor trellis, so the wisteria’s tangling vines would grow to have their twisting flower stems dangle from openings overhead. As the plant matures, the vine will become gnarled and woody, filled with blooms.

Other Kentucky wisteria cultivars include ‘Clara Mack’ which has white blooms and ‘Blue Moon’, a hardy cultivar from Minnesota with light blue blooms. The wonderfully fragrant blossoms first appear in early June and repeat through the summer. As Kentucky wisteria species bloom on current season’s new growth, it can be pruned in late winter or early spring before growth begins.

Avoid planting the Japanese wisteria species, (Wisteria floribunda). Although the vines may grow here, the Japanese wisteria will never flower, as flower buds are formed on last year’s wood will be killed by our cold weather. Another species, the Chinese wisteria (Wisteria sinensis), is even less hardy than the Japanese type. Both of these species types are rated zone 5, and also will not perform well in our zone 4 northern Iowa area

Wisteria grow best in a full sun location and prefer moist to average, well-drained soils, and needs regular watering – weekly, or more often in extreme heat. Apply a 2 inch layer of mulch to help retain moisture and control weeds. As wisteria is a legume, it does not need much nitrogen, as they are capable of fixing their own nitrogen.

Did you know? Wisteria flowers are a “wing-and-keel” flower structure. When the wings open, the keel is revealed. The underside of the flower is shaped with a hollow part, resembling a boat or the keel. Other members of the wisteria plant family (Fabaceae) such soybean, sweet peas and green beans, also have this type of flower form, from which seed pods are formed.

Gardening Questions? Contact McCormick at yvonne@iastate.edu for information or advice.