Long Flowering Clematis

edhelka

I keep reading that some clematises flower for 6 months (mostly the Boulevard collection but some others too). On Taylorsclematis, these are described as flowering from May to October (5-6 month, depending on how we count that, maybe 4 months if it starts on 31st May and finishes on 1st October ), these as May-Sep (4-5 months) and these as Jun-Oct (4-5 months).

Are these really that good? I would expect 2-3 months from a group 3 clematis (starting in July, finishing in early autumn). My Star of India is described as Jun-Sep but it only started in late July last year (it was newly planted, maybe it will start earlier this year).

Am I missing some secret (some varieties being significantly better than others)? Or is it just marketing? What are your clematises with the longest flowering season?

Fairygirl

Many do. Niobe [one of my favourites] comes into flower around mid to late May here, and is still flowering in autumn. 
The viticellas flower over a long season. From around June/July - again depending on your location and conditions.
A young plant will take several seasons to get into it's stride. 

mikeymustard

I bought a piilu last year which was in flower when I got it in June, had a bit of a rest after I planted it (it was blisteringly hot at this point, and I 'tidied' it up a bit) then flowered continuously from July into October. It's about to come out anytime now, so we'll see how it does this year

Edit: oh, and I forgot to say, I think the reason why boulevard varieties (and some others like piilu, ashva maybe? There must be lots of others) bud from pretty much all of the leaf axils not just the tip and 1st axil so they do offer a more staggered opening period. This theoretically means that the later top buds ripen while there's still lower flowers from earlier on

BobTheGardener

I have Polish Spirit which has just started flowering.  It's a large plant now with many stems from the ground so I pruned some stems as group 2 and cut the rest down as in group 3 pruning (done back in Feb.)  This has resulted in it having early large flowers now (from the gp2 pruned stems) and the new stems from the gp3 pruning are already showing small buds and will come into flower before the 'gp2 flowers' finish.  It will be continuously in bloom until the first frosts.  Worth considering using this method on other gp2/gp3 clems if a long flowering season is the aim and you have a suitable place in the ground.

LToby

My experience about clematis particularly the 'Clematis Marta' has the longest blooming period from Late Spring to Mid Autumn ... i planted this both in the garden and in pot. The one in the garden blooms shorter period from midSummer to early Autumn.

But the one i planted on the pot of which I moved around and been testing its sun exposure; I found that on its current location that will receive morning sun up to 7pm sun in Scotland (where I am), it blooms from Late Spring to Mid-Autumn beautifully and with lots of flowers ...

Most of them i found that they are particularly sensitive to sun exposure in order to bloom a lot. My neighbour has one that blooms terrifically in a partial shade... so try to understand where to plant in your garden ... 

Fairygirl

The other important point is - they're are thousands of clematis varieties 

Many are perfectly happy in shade too. Some of the darker ones, in particular, fade badly in too much sun, which ruins the appearance. 
Climate/conditions is a huge factor, which many people don't understand. The Group 2s for example, rarely flower much later in the year. It's useful to have something else nearby to continue the succession. 
Re what @BobTheGardener has said about treating some as a combination when pruning, you can also treat many Group 2s as Group 3s. That has the advantage of earlier flowers not getting frosted [as they often do here] and means you could have two Group 2s next to each other, but pruned differently, and flowering at different times.   

edhelka

Thanks everyone, really good answers!

I am somewhat bad with clematis, I don't give them as much attention as they deserve, but plan to change it.

What would you say is the smallest pot I could use for really small varieties and get away with it (with enough watering and feeding). If Bijou can be grown in a hanging basket, can I grow Boulevard varieties in 35cm pot reasonably well or do I need to be closer to 45cm?