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Why are these Wisterias Blooming in August?

We interrupt our regularly scheduled hollyhock program to bring you this anomaly:


Early this year, we had a spring freeze.

It often comes then. When the fruit trees are just starting to flower. And the wisterias.

This year, these wisterias got cut off just as their first buds were opening. They are the usual Wisteria sinensis, which means they have fat rather rectangular flower clusters, where all the flowers open more or less in a burst.

Wisteria japonica is the variety with the long, long, dripping clusters, sometimes over a foot. They open from the fat top end and then gradually bloom down to the tiny tip. They’re the ones you see on Japanese textiles, and in paintings. I grew one from seed I got from J. L. Hudson, and once I got it past the seedling stage, it wasn’t hard to grow. I’ve never gotten it to flower, though. This year I moved it to where it would get more sun, so maybe next year…

Wisteria really isn’t hard to grow, either sinensis or japonica. In fact, once it gets set in, it can make a bit of a pest of itself, so think about where you put it. I’ve known it to pry shingles off a house and push its way between the wall and the roof until it was growing (not very healthily) inside.

Wisterias like water, so if yours gets to this point, you might be able to starve it to where it doesn’t tear your house down. I’ve also noticed that while wisteria will rapidly take over anything, it also responds nicely to severe pruning. In fact, you make wisteria trees—a beautiful sight in bloom—by skilled severe pruning at certain stages in their lives.

Meanwhile, I’m curious about these particular wisterias. One white, one purple, both taking over the arbor per usual.

I have seen reblooming wisterias once, visiting in a town in a hotter climate, a couple of hours away. (Hot enough so they have oleanders on the freeway: plainly put, it doesn’t freeze.) It was June, and the wisteria was blooming. The people I was visiting said that their wisteria (a sinensis) often flowered again after the first spring bloom. I’d never heard of this; I was inclined to believe that theirs was a special kind of wisteria, a sort of reblooming sport.

Now, while the wisterias in these pictures didn’t exactly rebloom—they didn’t do more than open a few flowers in the first place–they did get into full bud at their usual time early this spring. And here they are in August, buds springing right and left. It looks as if they will shortly be covered in bloom.


Any ideas on how this happened? If there were a way a gardener could encourage this, I’d sure like to know.

Next post: Back to our regularly scheduled raving on hollyhocks.

Just so you know–I will be in the high mountains for the next two weeks. Posts will come up on schedule, but my replies may be absent until my return.

{ 8 comments… add one }

  • Mother Nature's Garden August 26, 2008, 2:01 pm

    It is an unexpected pleasure isn’t it?

  • Krys August 26, 2008, 2:26 pm

    Your wisterias are so beautiful — it’s nice that they chose to appear late rather than not at all. Definitely a lovely August surprise.

    Speaking of strange blooming patterns, I had a toad lily start to bloom in June. They usually bloom only in mid-September around here. In my last blog entry (http://urbanwildplants.blogspot.com/2008/08/what-do-you-think-has-it-been-strange.html), other bloggers have contributed their own observations of how strange this summer has been for them. Your contribution would be most welcome should you wish to make one.

  • Nancy Bond August 26, 2008, 4:39 pm

    How beautiful, and what a wonderful gift to see the summer out. :)

  • Sylvia (England) August 27, 2008, 3:11 am

    Pomona, Wisterias often re-bloom in late summer here in southern England. This second show is just a few blooms and nothing like the late spring show. My wisterias caught a late spring frost this year and I have had more blooms throughout summer than ever before.

    Best wishes Sylvia (England)

  • Pomona Belvedere August 27, 2008, 10:11 pm

    It’s true, this extra bloom is like a gift. I’m interested to hear that wisterias in southern England often re-bloom. Maybe I’ll try talking with these wisterias and see if they can be encouraged to keep it up…

    Krys, I found your post and comments about this summer’s oddities interesting, I hope more people go there and contribute.

  • jon August 3, 2011, 8:30 am

    I transplanted an old large wisteria tree last december it bloomed in the spring and is now blooming in august.. pleasant surprise.

  • Gaynor Laight August 30, 2016, 7:43 am

    Similar thing happened to us. In July half of our wisteria dropped all of its leaves – I accused my husband of cutting it back too hard. So we resigned ourselves to the fact it was dying – but last week flower buds and new leaves appeared. We were so happy.

  • Jean September 7, 2017, 8:15 am

    Interesting post.

    I’m on Long Island, in New York. I just noticed my Wisteria (sinensis Prolific) has quite a few random blooms on it. After it’s initial “full bloom”, it has randomly bloomed 3 more times this summer.

    The Hummingbirds like it. It gets a lot of sun. It’s growing over a wooden platform bird feeder.

    It’s September here- so that’s got me scratching my head. It gets about 6 hours of full sun daily, and it was unusually warm lately but we had torrential rain yesterday. Today it is 73 degrees.

    What would cause this interesting partial -rebloom to occur?

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