After considering the house and garden walls a man's next duty is to study his porch and pergola, and these introduce a new problem — the column. Here again the first question is not, "Which vine do I like best?" but "Is the architecture good or bad, refined or rustic?" For English experience seems to have evolved this principle: On beautiful columns foliage is more important than flowers; on rough columns flowers seem more important than foliage.
This principle grows out of the fact that leaf forms are displayed to the best advantage by a white background while flowers are usually best set off by a dark background.
Therefore, if your porch or pergola has classical columns of stone or concrete, the most appropriate climbers are those that have leaf forms of classic beauty, such as the wild grapes, the akebias, the kudzu, cinnamon, and Madeira vines, and the wonderful new species of Ampelopsis from China, in all of which the flowers are of secondary importance. Among the flowering climbers, roses, clematis, and wistaria have sufficient beauty of leaf form, but the following may be unsuitable: Honeysuckles tend to make amorphous masses; Dutchman's pipe has too gross a leaf; bitter-sweet is a little commonplace in leaf and wild in growth; matrimony vine too rustic.
On rough or temporary pergolas, the appropriate thing seems to be an exuberance of bloom. We often cover a whole porch or pergola with one kind of climbers, especially Crimson Rambler, which is too gaudy, and ought to give way to more delicate colours like the pink of Dorothy Perkins. The English believe that a variety of climbers is usually best on a pergola, provided the whole structure is well supplied with foliage, because then you have ever-changing interest, whereas the Crimson Rambler pergola flashes for a few weeks and is gone until another year.
Another thing we must remember about slender columns is not to overpower them with mighty growths of wistaria or trumpet creeper, which may weaken the pillars of piazzas.
Our greatest fault, however, is having too little luxuriance, for a pergola without vines on top is a failure and an absurdity. England goes to the other extreme. Luxuriance is too easy to get there and Mr. Robinson complains that many of their arbours are dank, close, sunless. In that moist, cool climate it is not so important to have shaded walks and covered ways as in a hot, dry climate like ours. But in both countries it is important not to have a porch or arbour smothered with vines. The effect should always be light and airy. Physical comfort alone would dictate this, but it is pleasant also to see all the leaves stirred by fresh air and an ever-changing play of light and shade on the floor, both in the daytime and moonlight.
One of the prettiest effects I saw in England is that of the Japanese wistaria (W. multijuga), which has clusters two or three feet long. These strings of bloom are so loose that they are not as showy on the ordinary porch as the common or Chinese wistaria, but when they are trained to hang down from the edges of a roof they have a liquid loveliness that is unsurpassed. The idea is, of course, Japanese but often one sees it well executed on English summer houses.
But the greatest wonder I saw in England is the collection of new species of Ampelopsis and Vitis from China. At Coombe Wood I had a feast of colour and form that I shall never forget. And to American nurserymen and collectors I would say, Wake up, try all the new species of Ampelopsis you can get. They may make a great difference in the appearance of American homes and gardens.