[Cali]

This year the leaves came out at the same time as the flowers opened on all three of my thirty-plus-year-old wisterias (each with a different orienation). Normally the leaves don't show themselves till at least two weeks after flowering. To my knowledge this has never happened before and I'm curious about the cause... hoping it's a one-off event since the effect of the flowers is totally ruined.

[Ina]

i have also a wisteria growing in my neighborhood so i will go and have a look. i passed a few days ago and i remember it having flowers but i am not so sure about the leaves...
i remeber seeing some Cercis siliquastrum having both flowers and leaves a few days ago and i found it weird...

[pamela]

I have seen this here in Spain quite often.  You are right the first effect of bloom is diminished somewhat but they are still lovely...... at least in my eyes.

[David Bracey]

Cali this type of effect usually happens when there is an a bout of unusual weather.....too cold, too hot, too dry etc for the time of year.  Flowering in the autumn following a mild autumn is often reported.  I`m not sure how long it takes from flower or leaf bud initiation in the meristem to emergence but clearly in the case of your Wisteria, the two caught each other up!

I assume you had a cold period this spring which probably delayed flowering (since they were initiated earlier than the leaves) but the cold weather did not delay the emergence of leaves.

Do we have a plant physiologist who could be more exact?

[Cali]

David, that makes sense, except I think it could be the other way round. We have had an unusually warm late March-early April. The flowering of the wisteria was at exactly the same time as every year. Maybe the unseasonal warmth made the leaves come out earlier than usual... is that possible?

[David Bracey]

Cali did you not have a cold period in Jan or February?  We did.

[Alisdair]

Down here in the extreme south of Greece - rather different from Cali's normal weather patterns - people's wisterias are flowering and in leaf, together, at the moment.

[Cali]

David, we did have a cold period in January and February, but that is pretty normal. What was unusual was the warmer weather in March.
Alisdair, it seems to be true of most of the islad here, except the North, where the wisteria flowered normally, with the leaves coming out a couple of weeks later.

[Ina]

I had a look at some wisterias near here and they also have flowers and leaves. the weather here is more similar to corfu. it could be due the very warm days we had for around 2 weeks...

[anita]

Hi Cali, I've gone back over my garden diary for a few years to check my notes and it seems from my observations in Southern Australia that if we get a warm spell while the Wisteria is about to flower the leaf development seems to be accelerated, resulting in the leeaves with flowers pattern you've experienced. I've also noted that my Wisteria which is a floribunda type seems to flower better after 'colder' winters - that is by our standards - maybe a couple of nights were it drops down to 1 or 2 deg. C. Those colder nights seem to help bud initiation... There are many more racemes in those years.
Also a note from my diary that's worth sharing... If you can get hold of the floribunda types they are worth seeking out. The longer racemes are much more spectacular. Anita

[David Bracey]

Cali,  I`m still trying to find a reasonable answer to your Wisteria phenomenon and have been doing some research on the internet. 

The time from flower bud initiation (FBI) to flowering varies for each plant species. For example Arabis (bittercress), probably the most researched plant species, takes about 13 days while Annona, custard apple, takes 33days. A Japanese reference said that FBI to flowering for Wisteria takes between half and one month.

Therefore, and this is a big jump, if Wisteria flowering usually occurs about April 1st (to keep it easy) we can assume that the FBI was made early to mid March.

For arguments sake, let`s say that LBI (leaf) takes the same time but some two weeks later then we can plot a time-line for your situation.

Thus FBI commenced early to mid March and proceeded normally until the warm period at the end of March/April with flowers emerging on April 14th. However LBI started two weeks later on April1st in the middle of the warm spell with emergence on April 14th, the same time as the flowers.

I wonder??? Hope it makes sense.