Climbers to hide wooden fencing

First, a word about 'climbers'. Climbers actually climb in three different ways - they twine (around a post or trellis support), or they use modified stems called petioles which will wrap around a THIN support like a pea stick or clematis mesh or, will stick by themselves, eventually, as new growth arrives. Your virginia creeper is in the last group - they need a bit of support initially, but once they've got going, they stick all by themselves. Your clematis is a petiole climber, so that needs thin supports to wrap round, and clematis mesh or green chicken wire is useful for that. Plants like honeysuckle and wisteria twine, and need a strong support to twine around to support their weight, so usually, a solid, non flexible panel of trellis, such as used in fencing, is best for those. So called climbing roses don't really climb at all - they just get very large, and usually will need tying in to a support or framework which has already been affixed to the fence or wall.

Hydrangea anomala is another self clinging climber, and like virginia creeper, may need a bit of support initially with canes until it gets going. All that said, you can see you probably need to consider what type of support you should add to enable your climbers to actually climb.

The next thing to consider, and which you haven't mentioned, is the amount of sunlight available in different parts of the garden - clematis, for instance, like their top parts in, if possible, full sun and their roots in cool shade, whereas Hydrangea anomala does well in shadier parts of the garden.

If your garden is small, then climbers are probably best, but if its not too small, consider cutting a border and planting things which are freestanding, but like to be in the shelter of, or against a wall or fence, such as Pyracantha, Ceanothus, Garrya elliptica, Cotoneaster horizontalis, and which can be clipped back to keep them against the fence. Euonymus Silver Queen is another which, if planted against a fence, will actually grow upwards against it.

Knowing what the sunlight availability is would be useful for more recommendations, along with which part of the country you're in - some plants which might grow well down south may not do so well a lot further north. And one last thing - if the soil is, as you say, very heavy clay, it would be best to dig it over where you think you want to plant, incorporating as much composted animal manure and horticultural grit as you can manage, bearing in mind that nothing should be planted less than a foot away from a fence or wall, not even climbers.

I am answering this with the point of view that you want to send climbers up your fencing which may or may not be your intention. If your fence is not treated wood covering it with growth will encourage and hasten rotting of the fence. If you have neighbors on the other side of the fence take the consquences of both wood rot and overgrowth to the other side of your fencing into consideration with a possible not too pleasant attitude from your neighbors. Questions to settle first is (1) is your fencing on or in your property line and (2) Did your neighbors put up any sums of money for the fencing when it was placed by the previous owner.