Wisteria is a stunning climber that can transform any garden with cascades of fragrant, delicate flowers each spring. Yet, many gardeners are frustrated when their wisteria fails to bloom or produces only a few blossoms. Understanding the reasons behind this common problem and knowing how to care for wisteria properly can help you enjoy a spectacular floral display year after year.
Wisterias are vigorous climbing plants that bloom richly in spring, either just before or during leaf emergence—provided that care and location are right.
Who doesn’t know the breathtaking images where wisteria transforms pergolas or facades into magical scenes at full bloom? But reality can look different. Sometimes the flowering is sparse or doesn’t show up at all. It doesn’t have to be that way! We’ll reveal the reasons why your wisteria might not be blooming or is only flowering sparsely and give tips on how to avoid this.
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Not All Wisterias Are the Same
Two species of wisteria—and their cultivars—are common as ornamental shrubs in our gardens. Wisteria sinensis is the Chinese wisteria. The name indicates its origin. The usually lilac-colored flower clusters are about 30 centimeters long and appear on bare branches shortly before leaf emergence, around mid or late April. About three weeks later, the Japanese wisteria (Wisteria floribunda) blooms. This species, as its name suggests, comes from Japan and has flower clusters more than twice as long, which appear simultaneously with the young foliage. A quick flower tip: When buying, always choose a proven, flowering cultivar with a name.
In Brief: Why Isn’t My Wisteria Blooming?
If your wisteria isn’t blooming or is only flowering sparsely, possible causes include a location with nutrient-poor soil or a missing or incorrect pruning. For a lush flower display, which appears on the plant’s short shoots, you should prune your wisteria at least twice a year: once in early spring before leaf emergence and once in midsummer after flowering. The main flowering can also fall victim to late frosts. Also, keep in mind that young plants only bloom after three or four years. It’s best to plant a flowering cultivar from the start.
Wisteria Not Blooming: Age and Condition Matter
Wisteria doesn’t bloom when it’s young. Expect that it will take at least three or four years before it produces flowers—and at the right location, the abundance of blooms will increase every year. Wisteria also needs at least a partially shaded, preferably sunny spot, and humus-rich, nutrient-rich soil. If it’s starved of nutrients, this will come at the expense of flowering. The plants can grow very tall and absolutely require a stable support structure. Only with proper support can the shoots be correctly guided and pruned—and the flowers showcased properly.
Late Frosts as a Cause for Missing Blooms
When wisteria blooms in spring, late frosts can still occur. Because the plant forms flower buds the previous year that develop after winter, these buds are vulnerable to late frost in unfavorable weather conditions. Especially for the early-blooming Chinese wisteria, the buds can be developed enough to be exposed to freezing temperatures without protection. In this case, the main flowering unfortunately fails, and only the early summer late bloomers appear.
Wisteria Doesn’t Bloom Without Proper Pruning
For splendid blooms, pruning wisteria regularly is essential. Those who let their wisteria grow without pruning will soon find a wild tangle of vines that offer few flowers. This climber just wants to grow upwards. Therefore, starting from the third year of growth, the plant should be pruned at least twice during the growing season. The first pruning takes place in early spring just before leaf emergence. The previous year’s side shoots are cut back to two or three buds—about ten centimeters. In midsummer, around two months after flowering, repeat this process, cutting the new side shoots back to 30 to 50 centimeters. This way, you create many more short shoots than the wisteria would naturally produce on its own. And only on these short shoots does the plant produce its flowers.
With the right location, proper pruning, and a little patience, your wisteria will reward you with breathtaking blooms that bring charm and magic to your garden. Keep in mind the plant’s needs and watch as it transforms your outdoor space into a fairy-tale scene bursting with color and life.
