Has anyone put a climber on a roof and had it grow down?

[bignamechangeroonie]

Bit weird I know. I have a roof that I can't use as a roof terrace but gets all the sun from about midday til end of day (east/west facing 'terrace').

If I could grow something on it in a pot and then trail it over the roof into the patio it would be great.

Any ideas? Not ivy though as it's just a spider house

[shovetheholly]

Is there a reason it has to be a climber and not a trailing plant? Something like a clematis repens or certain types of trachylospermum or perennial sweet peas are happy heading downwards. There are loads of smaller trailing rock plants too.

[RedBugMug]

I would also go with something like a clematis, jasmine, honeysuckle. lovely bee friendly flowers as well. you need to think about watering though. plants in pots need a lot of water, especially if it has lots of foliage.

[JeNeSuisPasVotreMiel]

Lots of climbers might be suitable for this but my first concern would be that you provide a big enough pot or planter, as having a large plant on a roof with no root anchorage might be an unstable arrangement.

You need to make sure that in a high wind your plant can't be lifted up or tipped over - to this end I would use the largest pot possible and weight/anchor it down.

Once this logistic is sorted, you could plant Clematis montana, or one of the rambling roses. (As long as nobody is likely to walk into branches hanging down at head height).

[shovetheholly]

Just a word of hesitation - trailing is a different biological mechanism from climbing (obviously, it's in the opposite direction - which means that in terms of light and gravity something slightly different is going on with the signalling!). Some climbers positively like to creep along the ground or trail downwards, others will really suffer if they can't climb, so it is worth looking for something that isn't going to try to keep shooting upwards, particularly if you're after a very dramatically trailing effect.

academic.oup.com/aobpla/article/doi/10.1093/aobpla/plv013/199896/The-behavioural-ecology-of-climbing-plants

[bignamechangeroonie]

I've ordered 4 climbing roses and was going to grow them up from the patio so they'd stretch towards the light at the top of the roof. It's just today I've thought about growing down instead.

The flat roof space available is about 10feet by 4 feet - it then inclines at the back so is quite protected. I wonder about a raised bed, not very deep that couldn't blow off ?

I can't use the roses I don't think as they'd need to be deep planted.

I love sweet peas, had no idea there were trailing ones.

[bignamechangeroonie]

Watering will be very easy, I've got an extending thingy spray.

I'm going to post a picture once I go over there and take it.

You're all really helpful

The 4 climbers I've bought as a pack from David Austin are : (any of those as roof possibilities?)

[Owllady]

Passion flower?

[shovetheholly]

OK, obvious stuff first - soil weighs a LOT. Planters, even fibre glass ones, add to that. And a mature plant can add kilos more. Make sure that your roof is capable of taking the weight of a large bed. The very last thing you want is for your lovely roof flowers to end up in your downstairs kitchen because the structure has given way!! I am currently having a structural engineering nightmare with specifications for a green roof on the basis of weights, snow loading etc. etc. etc.

I wonder if you'd be better off with a climber that then has 'falls' - the obvious thing would be something like wisteria, which you can grow up from the ground to whatever height you want, and then encourage to bloom with those downward cascades of beautiful scented flowers. You get verticality with this, without the weight, and the roots would still be in the soil, saving you the bother of watering etc.

You could still put something on your roof that would trail down, but you could make this lighter. A fibreglass trough with some of the light rock they use on green roofs, combined with a bit of soil, would allow you to grow some trailing alpines. (You still might need to check out weights though)

The perennial sweet pea is a slightly different beast from the annual one - it's not as scented and is a bit of a scrambling thuggish thing. It does like a bit of a root run, however, so I wonder how happy it would be in a pot - I've never tried it, and I suspect it might suffer a little? I think you'd need something else with it to give you more year-round interest.

[JeNeSuisPasVotreMiel]

Four climbing roses will take up a LOT of space - normally they will require 3m x 3m each, minimum, depending on the variety, sometimes more.

[bignamechangeroonie]

I was just thinking about putting one rose up there, not all 4.

If I had a decent sized square planter, like 6ft by 2ft I could put in a whole load of sweet peas plus a rose?

No issues with the roof, its massive and very strong looking (it's on top of commercial premises and not mine - and it's solely in my yard and they don't care if I use it to grow stuff)

[shovetheholly]

I am not a rose expert, so I could be talking out of my hat here, but I think I remember hearing that gravitotropic responses can be quite important in rose flowering with climbers - i.e. that they need to feel like they are going up before they go across. I COULD BE WRONG ABOUT THIS!

You can get roses that are designed to be ground cover, that are therefore happier crawling sideways. These may work better. You will need to provide a LOT of nutrients to any rose in a pot, I suspect.

You would not need more than one everlasting sweet pea. They are NOT like the scented annual ones! You can, however, get hanging basket annual sweet pea varieties that would work better for this idea.

[scanbran]

I tried this one year with a clematis (can't remember which type) as I had seen it on Pinterest. Needless to say it didn't work at all. I now use trailing geraniums which I think are just lovely.

[shovetheholly]

I think quite a few clematis have a fairly strong urge to grow upwards - so if you try to get them to go along the ground or down, they will resist! The 'repens' types are an exception - 'repens' denotes something 'creeping' that will be more happy going sideways!