A. Of all the general categories of plants, I find this has one of the most limited ranges to choose, especially if we stick to the definition of a self supporting (i.e.twining) plant.
The star of the show is probably Trachelospermum jasminoides (sometimes referred to as evergreen jasmine). This is very well behaved as it never goes rampant and it also holds its lower foliage very well which is a huge advantage on a fence. It is also sweet fragrant, flowers for a long time in the summer and seems to do ok even on a north face. No wonder it’s an industry best seller.
Further along the fence (and give it plenty of space) you could try Akebia quinata which has a maroon flower in spring. This can be slow to get started but once it gets some roots down can become triffid-like, so be prepared to prevent it strangling neighbouring plants. Like Trachelopsermum it retains its lower foliage well. Once established Akebias can produce a weird and wonderful sausage like fruit
On a sunny, sheltered section of fence Passiflora Caerulea (Passion Flower) has a splendidly exotic flower, but like Akebia it can be a bit vigorous. It can also get completely knocked back in a harsh winter, but the one in my garden seems to always bounce back. Don’t expect to get worthwhile passion fruit however, even in sunny Crouch End! (Passiflora edulis is the species grown in warmer climates for the fruit)
Solanum crispum “Glasnevin” (Flowering Potato) has fairly freely produced and enjoyable purple flowers. However, if you turn your back it will have grown into next door’s apple tree. And it doesn’t produce such dense foliage as the others. It’s a member of the toxic Nightshade family of plants, as are tomato and potato, so maybe be something to steer away from if you have young children.
Ivies are great for bees, shady locations and dense cover but can hasten the weathering of your timber fence and get very heavy if not controlled regularly.
It is also protocol in gardening answers to suggest a slightly more unusual example which will produce a “wow what’s that?” reaction. Let’s go for Sollya heterophylla which has terrific starry flowers from summer into autumn. The hitch is it is not very hardy and I confess to never having got one to survive more than three or four winters, but if your fence is south facing and sheltered it’s well worth a go.
Finally a comment on honeysuckles which some readers will have noted by their absence. I find these are disappointing on fences and perhaps also in North London. Others might disagree, but I have found that the two well know evergreen varieties Lonicera Halliana and Lonicera Henryi never do as well as their reputation suggests they should. Still no harm in trying.
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