Pelargonium

Read about Pelargonium in the Standard Cyclopedia of Horticulture

Pelargonium (stork, because the fruit is long and slender like a stork's bill). Geraniaceae. Geranium of gardens. Pelargonium. Stork's Bill. Many kinds of pot-plants, popular for indoors and for bedding; and some of them much planted permanently out-of-doors in California and elsewhere; flowers showy. Plants of various habit: some are fleshy and tuberous and are treated as succulents, but those commonly grown are erect or trailing leafy herbs or woody below (sometimes shrubby) with sts. somewhat soft and succulent or small and firm: lvs. mostly opposite, entire to decompound, stipulate, the foliage often strong- scented: infl. mostly umbel-like, on axillary peduncles; fls. irregular, the petals 5 (rarely fewer by abortion), the 2 upper usually larger and more prominently colored, the lower mostly narrow and rarely very small, the colors pink, red, purple, white, sometimes yellow, often attractively blotched or veined; calyx 5-parted (or the sepals said to be connate at base), the uppermost segm. produced at base into a slender nectar-bearing tube or spur adnate to the pedicel; stamens 10, of which 7 or less are anther-bearing and fertile: fr. of 5 valves, each 1-seeded and separating from the beaklike apex mostly by coiling and more or less hygro metrically.—Nearly all the pelargoniums are from S. Afr. All the species mentioned in this article are from that region, unless otherwise stated. Harvey, in Vol. I of Harvey & Sender's Flora Capensis (1859-60), admits 163 species; and his descriptions are followed closely in the characterizations of species given below. Knuth, the most recent monographer (in Engler's Pflanzen- reich, IV. 129, 1912), admits 232 species and very many well-marked hybrids. Pelargonium is distinguished from the genus Geranium by technical characters. In most cases, the fls. of Geranium are regular, but those of Pelargonium are irregular, the 2 upper petals differing from the others in size and shape and often in coloring. The most constant difference between the two genera is the presence in Pelargonium of a nectar-tube, extending from the base of one of the sepals and adherent to the side of the calyx-tube or pedicel. This tube is not seen by the casual observer, but it may be discovered by making a longitudinal section of the fl. and pedicel. The person who wishes to study the contemporaneous evolution of plants may find his heart's desire in Pelargonium. With great numbers of species and many of them variable and confusing in a wild state, with plant breeding in many places and continued through two centuries, and with a large special literature, the genus offers exceptional advantages and perplexities to the student. Most of the species early came into cultivation by the English and Dutch, the South African plants forming at one time almost a separate department of horticultural knowledge. P. cucullatum, the dominant parent in the florist's pelargoniums, was known in England as early as 1690. The two originals of the race of zonal or bedding geraniums were introduced into England in 1710 and 1714. Early in that century, a half-dozen species were grown at Eltham, in the famous garden of James Sherard, and these were pictured in 1732 in Dillenius account of that garden, "Hortus Elthamensis," a sumptuously illustrated work in quarto. Even at that time, P. inquinans had varied markedly (see Fig. 2836).in his "Species Plantarum," 1753, Linnaeus . described the few species which he knew (about twenty-five) under the genus Geranium. In 1787, L'Heritier founded the genus Pelargonium, and transferred many of the Linnaean species. L'Heritier's work "Geraniplogia," a quarto, appeared in Paris in 1787 to 1788, with forty-four full- page plates. Recently Kuntze has revived the pre- Linnaean name Geraniospermum (1736) for this genus, but it is not likely to find acceptance. Early in the nineteenth century, many species were in cultivation in Europe, and experiments in hybridizing and breeding became common. There appears to have been something like a geranium craze. The experiments seem to have been confined largely to the development of the show or fancy pelargoniums, as greenhouse subjects, for bedding plants had not reached their present popularity. The geranium interest seems to have culminated in Robert Sweet's noble work on "Geraniaceae," published in five volumes in London, 1820 to 1830, containing 500 well-executed colored plates of geraniaceous plants. At that time many distinct garden hybrids were in cultivation, and to these Sweet gave Latin botanical names. His fifth volume is devoted chiefly to garden forms of the show pelargonium type, to which the general class name Domes- ticum is given in the following sketch. The development of the zonal or bedding geraniums had begun in Sweet's time, and he includes them in his pictures, but the larger part of their evolution is subsequent to his history. Various small works on pelargonium have appeared. De Jonghe's "Traite Me'thodique de la Culture du Pelargonium," Brussels, 1844, contains good bibliographical and cultural data. Few classes of plants should have more interest to the amateur and fancier because the species are numerous and varied, the colors mostly very attractive, the habit of the plant interesting, and the foliage often with pleasing fragrance; yet, excluding the common window and bedding geraniums of the P. zonale and P. inquinans type and the Lady Washington or Show types, they are very little known to gardeners. A cool greenhouse could be made to yield very interesting subjects in the species here described and others that may be secured from collectors in the regions where they grow. Most of the cultivated forms of pelargonium may be grouped into four general horticultural classes: I. The zonal, horseshoe, fish, or bedding types, known to gardeners as "geraniums." They comprise a mongrel class, designated as the Hortorum class This race seems to be derived from P. zonale and P. inquinans. These two species were made by Linnaeus in 1753, but he founded them on descriptions in earlier works rather than directly on the plants. In America, the zonal geraniums are very popular, for they develop their colors well in the bright climate. They are popular in all countries, however. They probably stand closer to the lives of a great number of persons than any other ornamental plant. If a window or a garden can have but one plant, that plant is likely to be a geranium. The old race of large-flowered and large-clustered geraniums was known as "nosegay geraniums," because they were bouquet-like, but this term is not known in America. Another race has been developed for its zone marked leaves. There is also a race of double-flowered zonals, which have appeared chiefly since 1860. The very full double and close-clustered forms lose much of the grace and charm of the single types. Some of them are little better, to a sensitive eye, than balls of colored paper. In the development of the individual flower of the geranium, there have been two ideals—the English ideal for a circular flower with the petals broadened and overlapping, and the continental ideal with a somewhat two-lipped flower and the petals well separated. In the "Gardeners' Chronicle" in 1841, p. 644, the proper form is set forth in an illustration, and this is contrasted with the "original form;" the picture is reproduced, somewhat smaller, in Fig. 2837. "The long, narrow, flimsy petals of the old varieties," the writing says, "moved by every breath of wind, and separated to their very base by broad open spaces, have been succeeded by the beautiful compact flowers of the present day, with broad stout petals so entirely overlaying each other as to leave scarcely an indentation in the outline of the flower; while the coarseness which prevailed in the larger of the old sorts is replaced by a firmer substance, and a far more delicate texture." Fig. 2838 shows contrasting ideals, although the picture does not represent the extremes. In more recent years a French type has appeared under the name of "gros bois," or "large-wood" race. It is characterized as follows by Dauthenay: umbels ordinarily 4 to 5 inches in diameter: flowers very large; petals roundish, or sometimes triangular, the limb always very large and giving the corolla a remarkably round contour: leaves very large, thick and coriaceous, plane or incurved, more or less indented, strongly nerved, their diameter averaging about 5 inches, pedicels large and short: peduncles large, rigid, and projecting beyond the foliage: wood soft, fleshy, very large, often 1 1/2 inches around. To this type Dauthenay refers the Bruant geraniums, dating from 1882. A special handbook is devoted to these plants: Dauthenay, "Les Geraniums," Paris, 1897. II. The ivy-leaved geraniums, products largely of Pelargonium peltatum (Fig. 2839). The species is said to have been introduced into England in 1701. It is a weak and straggling plant, used mostly in vases, hanging-baskets, and other places in which an overhanging subject is desired. The foliage is thick and shiny, slightly peltate and prominently angle-lobed, and the pink or reddish two-lipped flowers are always admired. Much-improved and double forms are now in commerce. III. The "show" or fancy type is known to gardeners as "pelargonium," and in this country also as Lady Washington geraniums (Fig. 2845). These plants are very popular in Europe, being grown in numerous varieties. They are prominent at the exhibitions. Because of the hot trying summer climate, these plants are of very secondary importance in America, although there are many gardeners who succeed well with them. This race of pelargoniums seems to have descended chiefly from P. cucullatum, although P. angulosum may be nearly equally concerned in it. P. grandiflorum is also thought to have been a formative parent. It is probable that two or three other species are concerned in the evolution. In fact, the late Shirley Hibbard once wrote (G.C., July 3, 1880) that "it must be evident to every cultivator of these flowers that the blood of a score or so of species is mingled in them." This marked garden race, which represents no single wild species, is designated as the Domesticum group. IV. Various scented-leaved geraniums, known mostly as "rose geraniums." These are of several species, with then hybrids and derivatives. The common rose geraniums are nearest P. graveolens and P. Radula. The nutmeg geranium is P. odoratissimum or P. fragrans. Aside from the above groups there are several species which appear sporadically in -the trade, as P. tomen- tosum, P. echinatum, P. triste, P. quinquevulnerum, P. fulgidum, and P. quercifolium or the derivatives of them. Few great collections of pelargonium species and varieties have been made in this country, and this is much to be regretted. Culture of zonal geraniums. (C. W. Ward.) While the general florist may consider geranium- culture the easiest of all gardening, the fact remains that it is as necessary to observe the requirements of the geranium as it is to observe the requirements of any other plant; in order to succeed and produce the best effects attainable. While it is true that the geranium will grow and make a good showing with comparatively little care, there is as much difference between a skilfully grown geranium plant and one carelessly grown as there is between a fancy and a common rose or carnation. To secure the best results it is necessary to propagate from perfectly healthy stock. The dangers of over- propagation are as great with the geranium as with most other plants. To keep most varieties in good health it is necessary to plant the stock intended for propagation in the field and to propagate either from the field-grown wood in August or early September, or to lift the plants in the month of September and plant them on benches in the greenhouse, where they will become established and will maintain a vigorous constitution throughout the winter season. The propagation from field-grown wood is far less successful than from wood grown inside, and when the field-grown cuttings are placed in sand, a large percentage of them is likely to damp-off, especially if there has been a comparatively abundant rainfall in the month of July. The best method that the writer has found for striking the field- grown cuttings is to put them in 2-inch pots, using a light sandy soil free from all manure and chemicals, and to place the pots in the full sunlight either in a coolhouse or a frame. These cuttings must be kept on the dry side until the calluses have been well formed, although they should not be allowed to shrivel at any time. If the cuttings show signs of shriveling, a light syringing is preferable to a heavy watering. After the roots have started, the treatment of the plants is the same as if the cuttings had been rooted in the sand and repotted. The writer contiders wood grown inside superior to field-grown wood, as the cuttings are much shorter-jointed; most of them can be taken from the plant with a heel and 95 to 100 per cent of them will root in sand in the ordinary cutting-bench. A good temperature for the geranium propagating- house is 56° to 60°, with a bottom heat of 65° to 60*. While the cuttings are in the sand and before they are rooted, care must be taken about keeping them top moist for fear of "damping-off," or what geranium- growers know as "black-rot." As soon as the cutting is thoroughly callused and begins to emit roots, it should be potted up at once. The best soil for geraniums, according to the writer's experience, is a firm pliable clay loam; this is best if used absolutely without any manure, especially fresh manure. After potting the cuttings they should be lightly watered and shaded for a day or so if the sun is extremely hot, until the roots take hold and the foliage fills up and the stems begin to look plump. The geranium should not be grown at any time in its young state in a soil that is too rich, and care must also be taken that the plants are not kept too wet. The geranium is subject to few diseases, and so far as the writer has been able to observe these diseases are brought on by improper treatment, such as having too much fresh rank manure in the soil or keeping the plants too wet. Too much strong plant-food in the earth combined with too much moisture induces a condition of the leaves ordinarily called "spot." It usually appears in the hottest weather or immediately after extreme heat accompanied by copious showers or rains. Excellent specimen geranium plants may be grown in pots, especially of some of the newer French and English round-flowered varieties. In order to produce the best results, choose young vigorous plants that have been propagated either in the latter part of August or the forepart of September, and that have shown a disposition to take hold immediately, both in rooting and in starting to grow after being potted. The soil should not be too rich, and it is best to start with the plant in a rather small pot, say 2 1/2 inches, and proceed onward with light shifts,—that is, shifting the plant from a 2 1/2-inch to a 3 1/2-inch pot, and so on, letting the sizes increase an inch at each shift until a 7-, 8-, or 9-inch pot is reached, which will usually be large enough to flower the finest specimens. Whenever shifting the geranium, be sure to pot firmly, as a firm soil produces a short-jointed stocky growth, and far more bloom than a loose or over-rich soil. When the plants reach a 5- or 6-inch pot they may be regularly fed with manure- water. The most critical time for these specimen geraniums will be in the months of July, August, and September; in these periods exposure to intense sunshine should be avoided. Too much water and a close temperature are always detrimental to the geranium. Syringing the foliage frequently to keep down the temperature is also injurious. If these plants are kept under glass, a light shading or stripping upon the glass is beneficial. Probably the best position for such plants in these three extreme months is on the north side of a row of trees, some distance away from the trees, where the plants will have the benefit of the subdued shading of the foliage. If kept under glass and shaded,abundant ventilation should always be provided. As the winter approaches, a night temperature of 60° and day temperature of 70° to 75°; with plenty of ventilation in the daytime, especially in bright weather, seem best to suit the plants. Syringing ruins the flowers, and too much moisture either in the pot or upon the foliage causes the spotting of the leaves known as "dropsy." In planting the geranium in the field or in beds, always avoid an over-rich soil. The earth should be in good condition and fertile, but must not be loaded with either chemical or animal fertilizer. Too much water at any period during the hot weather produces a rank growth, reduces the quantity of bloom and in most instances induces the spotted foliage to appear. Another disease, which is sometimes serious, especially in extremely hot seasons accompanied with a superabundance of moisture, is "stem-rot." This frequently attacks imported stock. It is most serious in intensely hot seasons; the entire plant turns black and fades and withers away. The stem-rot occurs in varieties that have been very heavily propagated. The insects that affect the geranium are also comparatively few. The red-spider is sometimes a serious pest in summer and is difficult to get rid of when it is once well established. The only method is to syringe the plants with an extremely fine spray, and also to pick off the leaves that are seriously affected and burn them. The green-fly is also troublesome at times, but is easily managed with the ordinary fumigation of tobacco. There is a small caterpillar that eats the foliage and sometimes proves a serious pest. If one can induce a few ground sparrows or any of the warblers, or even English sparrows, to make their home about the greenhouse, they will put a speedy end to these caterpillars. Another remedy is to go over the plants carefully and to pick the caterpillars off and destroy them. This is tedious, as it must be done frequently. In the way of bedding geraniums, as a rule the Bruant section produces the best results, but there are a number of English and French varieties that do especially well in our hot climate. The greatest difficulty in successful geranium-culture in America is the intense heat of the summer months, chiefly July and August. Some varieties withstand the heat better than others. Show pelargoniums. (T. D. Hatfield.) What are known as show pelargoniums have enjoyed a long popularity. By the general public, and by old people especially, they are known as Lady Washington geraniums. They are not so commonly grown as the so-called geraniums, chiefly on account of their limited season of bloom and the fact that they cannot endure our hot midsummer suns. Through the greater part of the summer they are liable to be neglected. They also require different treatment from geraniums, and — if skill there be — more skill in cultivation. At the end of the blooming season, they require rest, — a season of ripening the growth already made. At this time very little water will be needed, and they may be stood out in the full sun. Only the old flower-stems may be removed. In no sense should they be cut back at this time, neither should water enough be given to encourage new growth. All the leaves should stay on until they naturally turn yellow with age, thus securing a thoroughly ripened growth. In September, one may prune them into shape, sometimes rather severely, but in any case cut out all weak and soft shoots. They should then be shaken out and repotted in a light compost, not rich, into the smallest-sized pots that wil The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.

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