Wisteria not flowering.

Design Bod

Hi All, We inherited a Wisteria growing against the back of our house when we moved in a couple of years ago. It didn’t flower last year or this (so far).

It’s planted in a gap in the paving so we can’t access the roots to chop into them. It’s got so many leaves that I assume it has too much Nitrogen in the ground ... I’m wondering if we should add some Phosphorus fertiliser at some point to help balance out but not sure when?

Also, what should we do about pruning? Any tips? It’s rather a thug and grows up v v quickly to cover windows, as you can see, so we do need to chop the tops off at the very least. It faces East, by the way.

Any tips much appreciated! Maybe third year lucky!

PS you’ll also see a sad looking Clematis to the left which doesn’t like that position so is going to be moved.

Emerion

I’m not an expert, so others might know better. But first thing is when and how have you pruned it? There are loads of explanations of pruning wisteria on the web, but simply, you need to cut long, unwanted lengths back in autumn to 4-6 buds, and then prune again in late winter to a couple of buds. That’s where the flowers come. Also, some  wisterias take a few years to start flowering. Yours looks a good size, but so did ours before it started, and I was convinced there was something wrong with it. But it did start eventually without us doing anything extra. Do you know how old it is?

Guernsey Donkey2

Hello Design Bod, does your wisteria get any sun on it?  Could the plant be suffering from cold, the clematis too, they both like sunshine.  Perhaps the clematis pot is too small, depending on the variety. Are they staved of water or a lack of feeding perhaps?

Design Bod

Hi @Emerion, I must confess that there has been no 'horticultural' pruning thus far apart from some major growth pruning last Spring as it was climbing over all the windows and up into the underside of the eaves of the roof. We need to improve on that and do as you suggest in order to improve the chance of it flowering.

Is it best to avoid any stem pruning now but wait until the Autumn now?

We don't know how old it is, unfortunately, or if indeed it ever has flowered (or even its colour).

Hi @Guernsey Donkey2 - yes, it's East facing so gets some very hot sun for the first few hours of the day. Then the sun moves round and it gets no direct sun thereafter. Re. feeding, I wasn't sure if I should give the Wisteria a Phosphorus feed in case it was getting too much Nitrogen - any thoughts on that?

I think the strong Easterly sun is what's ended up frying the poor Clematis. Thanks for the suggestion of the pot size. I don't know the Clematis variety but it probably needs a feed too. Last year we were moving in so the garden was not the focus but I'm hoping to get more across things from this year onwards. 

Obelixx

The RHS gives very clear advice on pruning wisterias and it should be done in July and Jan/Feb - https://www.rhs.org.uk/videos/advice/pruning-wisteria and https://www.rhs.org.uk/advice/profile?pid=242

Giving it rose or tomato feed may also encourage flowers to form.

As for the clematis, it is probably hungry and thirsty so, if you can, double the pot size and give it good John Innes no 3 compost with about 20% multi-purpose to help with moisture retention.  When you re-pot, water it thoroughly first and then set it 4"/10cms lower in the new pot than it was in the old and fill the gap with compost and leave an extra inch or two between final compost level and the rim to allow for watering.

Clematis are hungry, thirsty plants so you need to give it a generous feed of slow release clematis/tomato or rose fertiliser every spring and then regular feeds form spring thru to mid summer when watering.  Liquid rose or tomato food will be fine or else seaweed.  You will need to water it regularly and that means once a day in hot spells.  Treated well, it will reward you with fine foliage and flowers and then you can identify it and that will tell you its pruning group.

purplerallim

Last year was unusual so whatever happened in your new garden was probably not the way it does usually.  Take this year ( hopefully) as an indication of what does well so you can decide what to keep. What needs moving and where there is an opening for something new. It takes a year to get to know what is in it, so take it slow and enjoy.

Emerion

If last year’s spring pruning was drastic, you might have removed that year’s flower buds, but there should be some more there now. Hopefully someone else will know how late you could cut it back now whilst leaving time to allow next year’s buds to develop. I would think there’s time, but I’ve never done it. I’ve never fed mine, just keep the ground in good heart, but I can see that your situation is different. I seem to remember that my neighbour where I used to live used rose feed on his wisteria. 

Mr. Vine Eye

Hi Design bod, just to point out that Eastern facing is not strong sun.

In fact, apart from North facing, East facing is the coolest position to be in.

Its a good position for many plants that need part sun, but not full sun, as they get shade in the afternoon.

Morning sun is far less intense than midday and afternoon sun. It's unlikely that anything would get frazzled from morning sun. Unless it was a plant that required deep shade at all times.

Wisteria are fine in that position but I believe that South or West facing are recommended for them as that gives them the strongest sun exposure and they are happiest in Full Sun (fine with part sun but may not flower as much - according to RHS anyway)

It probably is down to the lack of pruning - if you start following the guides for summer and winter pruning then I'm sure you'll start getting flowers soon.

Can you tell if the plant has been grafted, looking at the base? It's likely, which is a good thing. I only ask because wisteria grown from seed can take decades before they flower.

Design Bod

Hello All, many thanks for the thoughts and advice and apologies for the late reply.

Hi @Obelixx and thanks very much for those links. Do you think I can do any pruning now of the tendrils that are climbing up over my windows?
I was uncertain whether to give it any Nitrogen feed as had read that it may have too much of that already from the soil if it’s overly leafy so may need a Phosphorus feed instead. Do you have a view on that?
Many thanks for the Clematis advice, I’ll get on with that at the weekend 😊

@purplerallim , those are very wise words. Last year passed in a flash and the weather was quite extraordinary so it was hard to get our bearings with the garden, especially as very much a newbie. Have been on a steep learning curve since!

@Emerion yes, the top pruning was certainly drastic, but had to be as it was rampaging into the roof underside. It is a shame that we can’t really get to the soil, which doesn’t help. I think correct pruning will help for sure.

@MrVineEye You’re quite right about the Easterly sun, although during last year’s Summer it was certainly scorching. The Clematis’ leaves burnt to a crisp! I think the house wall heated up as well which didn’t help. Unfortunately we don’t have any suitable South or West facing walls.
I can’t tell if the plant has been grafted - am a bit clueless on that front - is there something I can look for that would tell me? I’m very tempted to email the former occupants and ask them if it’s ever flowered, which would at least solve the mystery, and then just leave me with the challenge of how to make it flower!

Thanks again everyone! Any tips on whether I could do any minor tendril snipping now, just to clear the windows at least, would be much appreciated!

purplerallim

With the size of your plant I doubt it would miss the odd stem.🙂 So give it a tidy up if that's the need.

Design Bod

Thanks @purplerallim It’s turning into a beanstalk!