Surprisingly, you can plant some of the more tender shrubs against a north wall. North would seem to spell cold, because the north wind really does give rise to some of the coldest winter days. But. in fact, most frost damage to plants arises through over-rapid thawing of frozen tissues in early spring, and this occurs when the early-morning sun strikes them. Hence more damage is likely to arise when plants face east than when they are tucked on a slowly warming north side. however there aren’t many evergreen climbers with attractive flowers anyway – and few plants produce as many flowers when facing north as they do in a more sunny spot.
Here are some of the best options:
This is the star jasmine. It takes two or three years to settle down and is rather too tender for exposed or cold gardens, but it’s self-clinging and clothes the wall with fairly small, elliptical and very glossy, dark green leaves. Towards the end of the summer it produces masses of white, jasmine-like flowers with a rich perfume.
Among evergreen honeysuckles, Lonicera japonica is the most frequently seen and the best known. The flowers are fragrant, large, white becoming yellow later and appear, even on north-facing plants, throughout the summer. This is a vigorous plant, and although it reaches its greatest growth in a fairly sunny spot, it needs a large wall wherever it is planted. The related L. semper-virens will also succeed on a north wall. Its flowers have yellow interiors with scarlet on the outside.
Pileostegia viburnoides is related to the hydrangeas. It grows much more slowly than the honeysuckles and has long, narrow and rather leathery leaves and masses of creamy-white flowers late in the summer. It is self-clinging and. as it benefits from shelter, it is an especially good choice for a north wall.
The self-clinging, evergreen climbing hydrangea, Hydrangea serratifolia is much less well known than its deciduous counterpart. H. petiolaris, possibly because it is more tender and its flowers less spectacular. It is perhaps best considered as a very good foliage plant, with its large, dark glossy leaves, consider its creamy-white flowers as a bonus.
Holboeuia coriacea is another valuable plant. A vigorous grower, it can reach 20ft. Rather unusually for an evergreen climber, it bears its flowers, which are greenish-white, early in the season – in April-May. The dark purple, pea-like pods remain after the flowers have faded.
Because of the protection afforded by a north wall, some flowering climbers which are normally deciduous will retain their leaves through mild winters. Some roses come into this category, including one with attractive greyish-green foliage, Rosa brunonii ‘La Mortola’.