RECOMMENDING VINES makes me nervous. Once I recommended the elegant polished Kadsura japonica to a gardener for a fragile little canopy over the kitchen door, but the gardener instead got kudzu (on the theory that one Japanese name is very like another, you hear one and you've heard them all) and it took off the roof.
For all that, the climbing knotweed is in flower (Polygonum aubertii) or the fleece vine or the silver lace vine.
The great thing about it is that its ovalish leaves of medium deep green are free of disease and bug. It does not need to be sprayed.
It does, perhaps, need to be controlled.
If you have a vast old dying tree in the back, nothing is better than this vine for covering it.
Its first year it grows to 25 feet and its second year it grows to 40.
In the days people wanted to cover old barns with something green (now old barns are too valuable for such nonsense) this vine was the perfect choice.
It is as good as it ever was for conceling a really awful garage, and if you happen to have a warehouse wall to deal with, this will solve much of your problem, and the trumpet vine, Campsis 'Madame Galen' will do the rest. y
The knotweek begins flowering feebly in June and by August almost every growth is tipped with a slender three or four inches long, lined with tiny whitish flowers. The general effect of a large vine in bloom is of green covered with light sea foam.
It is not at all what you want for trailing over a delicately wrought iron railing. The vine twines (a chain is useful for getting it up to the top of that warehouse wall, by the way) and it can soon make mincemeat of any flimsy trellis.
But it is wonderful for producing a liana effect in the city. It likes sun and good soil, as most plants do, but I would not hesitate to give it less than ideal conditions. It is hard for me to imagine it not growing.
In gallon cans from garden centers it can be transplanted even in hot weather. Otherwise it can be ordered from nurseries for delivery in the spring.
The flowers are somewhat scented. While the floral effect is hardly comparable to a climbing rose in full cry, still the knotwood blooms in August and looks cool and fresh and luxuriant and happy (as many roses do not).