Clematis question

KeenOnGreen

One or two of our Clematis are not thriving (only planted in 2019).  I think they need more feeding and water, and more shade at the roots.  I thought we could make a small four-sided box to fit around the roots.  About the size of a tin of Quality Street (other brands are available) in dimension.

We will use fencing panelling, so only about 4 inches high, and the top and bottom will be open to the air/soil.  The idea is to then fill this with well-rotted manure, so that it gives them nutrients, and retains more water for them.

Q: Do we risk the stem rotting?  I assume not, as  you can bury them deep when planting them, but just wanted to get advice from someone more experienced at growing them.  If you have any interesting set-ups that do similar, would love to see them.

Fairygirl

What types are they? Were they on the small side when you planted them?
It's usually just water they need more than anything, unless it's the alpina or koreana types etc, which like drier conditions.

KeenOnGreen

@Fairygirl  One is a Jackmanii, which put on lots of growth and flowered last year, but which got very bad mildew.  I cut it back hard after flowering and it put on lots of growth, so I was hoping it would thrive this year.  It has barely grown at all, and has only done so in the past fortnight, as I began watering it daily.

The other one I lost the label from.  It is an early flowering variety, and has reached the top of our fence, but the leaves are tiny, much smaller than they should be, and not very vigorous.  It is probably planted too close to the fence (we are guilty of this will all of our Clematis).  We don't have any of alpina or koreana varieties.

I'd like to make the boxes for all of our Clematis, even the ones that are doing well.  

Fairygirl

Mildew is pretty common if they lack water. Too close to fences/walls is also tricky. A bucket of water every few days is better- encourages them to get right down into the soil further down,and then it's easier for them to access it if it's a bit dry.
Is the 2nd one a montana? The foliage on them is slightly different from the bigger flowered ones, and they can take a while to get going,then they take off. 
Were they mature plants when you planted them?

I'm not sure a Quality St tin size would make a lot of difference, and I'm very familiar with the size of those tins 
Have you got any pix?

Nollie

I’m a clematis newbie, so can’t advise on your plants but probably better to mulch with manure or compost outside the box - to keep even well rotted manure away from direct contact with the stems. It will work it’s way down, especially of you also water outside the box. Would you agree @Fairygirl or am I talking b*llocks?

Stevedaylilly

Hi 
Really no need to build a open box just lay the mulch around the base of the plant about 2” deep. Keep it away from the stem by allowing a 3” gap all round. This well then make a reservoir for deep watering. I would then give them a foliar tomato feed every 2 weeks until flowering (my Clematis normally flower very strong due to feeding them) 
For shade, I would plant a suitable tall perennial plant in front of the Clematis that will give it sufficient shade to the base

Fairygirl

The 'shade at the base' thing is another myth. They need their roots to be damp. 
I just put mulch over them - if they're the type that are happy to be deeper.
I use compost for that though. 
I don't really feed mine either - they get a bit of B,F&B in spring and that's about it. I occasionally give the ones which flower a second time [Group 2s]  a feed, but they don't flower much here after summer anyway. The viticellas just keep flowering by themselves without any problem.
Water is what they mostly need. Richard, who owns Hawthorne's Clematis, and sometimes posts on the forum, will tell you that's the case. 
@Nollie - it's why I asked @KeenOnGreen if they were mature plants. If they were young plants last year, it may simply be that they're immature. I don't really use manure - unless it's when I create a new bed/border. 

Stevedaylilly

Hi Fairygirl

With all due respects I think the base of a Clematis in shade is not a myth, based on my own experiences (23 healthy Clematis to date)

Shade at it’s base and the upper growth in the sun is the best aspect for pruning groups 2 & 3.
I agree a moist, well drained soil is what Clematis love and a mulch in spring is most beneficial. Mulching improves moisture retention to the soil but would soon biodegrade over a few months. Therefore , a shaded base is more beneficial that full sun just for reduced water evaporation and therefore keeping moisture to the surrounding soil 

KeenOnGreen

I have a Montana, which is 3 years planted, and doing fine.  All of my other Clematis were planted last year, so still getting established.  Most of them are doing well, but the two in particular that I mentioned above are the problem.  They are reasonably shaded at the roots by other shrubs, and their tops get sun.

Based on what people say above, I'll avoid using the boxes.  I have already spread some well rotted manure around the roots, give them a weekly tomato feed, and I'll water regularly.  It might just be the case that they need another year or two to get more established.  We have had a very hot and dry Spring in London, I suspect that has been a significant factor.

Fairygirl

Water is what they need by the sound of it @KeenOnGreen.
I followed Richard Hodson's advice re water [Hawthorne's Nursery] and although we get more than enough consistent water from the sky here, even in summer,  it definitely helped one or two of mine, as we had some much drier spells on the last two years.
I can afford to plant mine where others might struggle, because of our climate, but where you are, it might be much harder to keep them hydrated too. It can certainly take them a couple of years to get going - and growing!