They are sometimes used as "dot" plants in large beds of low-growing subjects, where they serve to break the flatness. In England, where standard roses are used much more freely than here, certain varieties are considered much less subject to mildew when thus grown.
There are three methods whereby standard plants are produced:
Standards produced by grafting include such plants as "tree" Roses, budded on Rosa rugosa, (R. canina is commonly used for this purpose in England); Umbrella Catalpa is budded on Catalpa speciosa; Weeping Mulberry, budded or grafted on White Mulberry; Camperdown Elm on Ulmus glabra; Weeping Spring Cherry on Prunus subhirtella; and Sophora japonica pendula (Weeping Scholar Tree) on S. japonica.
The Roses and Cherries are budded in July and August; Catalpa is budded in June—using buds from shoots kept dormant in cold storage; Mulberries may be grafted in April or budded in July; the Camperdown Elm is grafted in May or budded in August; and the Scholar Tree is grafted in the spring. Unless you are familiar with the technique of budding and grafting and have suitable understocks available, perhaps it is better to purchase plants of this nature from a nursery rather than to attempt to "roll your own."
Of course, if you are in no special hurry to obtain specimen standard plants and will not be discouraged if you have a few failures, go ahead and do your own grafting—you will find it full of interest. The proper techniques to be followed can be learned from almost any book on general gardening; from all books concerned with plant propagation; but best of all from visiting a nursery when grafting and budding is in progress.
The second method—that of cutting back an established plant and then allowing only one shoot to develop—does not demand any difficult technique and may be adopted with a large variety of plants. We have used it successfully with some of the climbing roses—Hiawatha, Miss Flora Mitten, and Ben Stad being the ones which gave best results. Young plants are set out in spring or fall and allowed to grow at will for one year.
The following spring the plant is cut down to the ground and, when it starts to grow, all shoots but the strongest one are rubbed off. The shoot that is left is supported by tying it to a stout stake. When this shoot has attained the required height its tip is pinched out to induce side buds to grow to form a head. The side shoots, in turn, have their tips pinched when they have attained a length of from 6 to 12 inches.
When a sufficiently branching head has been acquired, further pinching is unnecessary. Of course, any shoots which originate on the stem below the head must be rubbed off as soon as they are discovered, except that, in the case of roses, if an additional strong shoot should develop from near the surface of the ground it is well to leave it as a reserve in case of accident to the first shoot.
The general procedure outlined above is applicable to many hardy woody plants. Among those suitable for standards but which may require permanent support for their main stem are Wisteria and Grape. Some are capable of self-support once the head has been formed. In this group we have such shrubs as Bush Honeysuckle, Peegee Hydrangea, Privet, and Azalea. When trees are grown as standards a bare stem of suitable height cannot be developed in one year and the training must be spread over several years. Maple and Linden are among the trees sometimes grown as standards with the top trimmed to a square or rectangular "head."
So far we have been dealing with hardy plants. Fuchsia, Heliotrope, Oleander, and Pelargonium can be trained as standards and are valuable for summer display outdoors, but, ideally, they should be stored in a greenhouse during the dormant season. If a greenhouse is not available a cool cellar kept between 35 and 45 degrees is an acceptable makeshift. When a cellar is used very little water should be given, thus making the plants go to rest to pass the winter in a more or less moribund condition.
The third method—that of starting the training in babyhood—is applicable to a variety of plants, Fuchsia, Heliotrope, Lantana, Pelargonium, and others, but is especially suitable for "one season" standards formed from Chrysanthemum, Coleus, Petunia, and Verbena. When following this method great judgment. must be exercised in removing side shoots. The aim is to stimulate the growth of the main shoot until it has attained the desired height, and usually this is best accomplished by the complete removal of all side shoots.
But the plant must carry enough leaves to nourish the roots. If the leaves on the main shoot are large and vigorous they may be sufficient, but if they are not, the side shoots should be allowed to grow a few inches before they are checked in order to provide enough leaf surface. Later in the season, when the head is being formed, the laterals below the head may be cut off close to the main stem.