This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
E. pulcherrima and E. fulgens are good winter-flowering greenhouse plants, and require special treatment. E. fulgens succeeds well in the warmest parts of the house, in pots, or best planted out like roses and trained upon the wall or strings. It is propagated from cuttings taken in June, when the old plants have started to grow, kept in a warm frame until rooted, and then kept growing with heat, any transfers being made with as little root disturbance as possible. If stocky show plants are wanted, several cuttings may be planted in one pot and checked two or three times during summer by repotting, and kept pinched back freely to secure branches. They are best kept cooler when in flower, but are very sensitive to cold or sudden changes in temperature. After flowering they are kept dry for a few months. For the cut sprays they are best grown from cuttings each year. They last very well when cut.
The culture of the poinsettia is very similar. To secure plants with large heads, the general plan is to grow from cuttings annually, but the old plants may be continued. Old plants that have been resting may be introduced to heat and moisture in late spring, and will soon give a liberal supply of cuttings, which are usually taken from the young wood. Successive sets of cuttings may be made at later periods if different-sized plants are wanted. When well started, the potted plants are plunged outdoors till September, with plenty of water, light and sunshine and good drainage. They do well in rich heavy loam in 5-7-inch pots. They are liable to drop their leaves if exposed to cold or other unfavorable condi-tions. In autumn they are transferred to the greenhouse, with moderate temperature. When the bracts begin to appear, give more heat and some manure water to expand them. When in flower, reduce the temperature to preserve them longer. After flowering the pots may be stowed away in a dry warm place till spring, - under the benches will do. When the buds are cut the great objection is that they wilt easily. This may be obviated by keeping them in water for a few days before using.
See Grieve, G.C. III. 9:106, and Hatfield in Garden and Forest 9:496. See article Poinsettia for further treatment.
Euphorbia splendens is another winter bloomer, and may be treated as the succulents, with more heat and water. It will do well in living-rooms, and bears some flowers all the year. It bears rough treatment well, and is propagated by cuttings from the young growth, which root with the greatest ease.
In tropical and subtropical regions many of the treelike or succulent euphorbias make fine outdoor ornamentals. The poinsettia is a magnificent landscape ornament in California, West Indies and so on. In Southern California the poinsettia is propagated by sticking canes 3 feet long in the ground from April on, these growing and blooming, often profusely, the first season. In the West Indies and Florida, some of the thorny tree-like forms, especially E. lactea, are grown as hedges, their thick, erect thorny branches making an almost impenetrable barrier. This and other species are grown also as specimen plants. See Succulents.
Fig. 1439. Euphorbia fulgens (X 1/3). No. 5.
A. Glands of the involucre with petal-like appendages (almost none in 4).' slender-branched herbs or rarely shrubs not spiny: leaves entire. Section Adeno-petalum. The Section Anisophyllum, genus Chamaesyce of some, differs in having small opposite leaves, unequal at base, stipules present, flowers small, glands 4. It contains most of the low herbaceous wild euphorbias of U. S., such as E. mac-ulata, Linn., E. Preslii, Guss., E. serpens, and E. capitata; names from this group occur in American catalogues, but the species to which they properly belong are inconspicuous weeds. E. lorifolia, Hillebr., of Hawaii, has recently been investigated as a possible source of rubber. (Descriptions of these species will be found in the floras.)
B. Stipules present.
(E. variegata, Sims). Snow-on-the-Mountain. Ghost-Weed. Fig. 1438. Annual, about 2 ft. high, pubescent, dichotomously many-branched: leaves numerous, light green, ovate-subcordate to oblong-lanceolate, 1-3 in. long, the upper white-margined, often entirely white: involucral glands with large white appendages. July-Oct. Plains from Dak. to Texas and extending eastward. B.M. 1747. Gt. 30:218. V. 2, p. 281; 5, p. 64. G.W. 13, p. 305. - Hardy annual, used for its white foliage in bedding and mixed borders in sunny situations.
Fig. 1438. Euphorbia marginata (X 1/3) • No. 1
(E. haematodes, Boiss.?). A tall shrub: lvs, ovate, obtusely pointed, in whorls of 3, red when young to deep bronze or purplish red later. - This handsome plant of unknown nativity is cult, in S. U. S. While it is not possible to classify it exactly without flowers and fruit, the foliage characters indicate its relationship to E. cotinifolia, Linn.
bb. Stipules absent or microscopic.
c. Plant a perennial herb.
(Tithymalopsis corollata, Klotzsch & Garcke). Flowering Spurge. Fig. 1437. Plant 1 1/2-3 ft. high, usually glabrous, slender and diffusely branched above: leaves ovate-oblong to lanceolate, 1-2 in. long, those of the infloresence much smaller and opposite: involucral glands 5, with conspicuous white appendages. July-Oct. On rather dry soil E. U. S. B.M. 2992. L.B.C. 4:390. F.R. 1:969. - A hardy herbaceous perennial used like gypsophila for cutting, and as a bedder in light soil. There are many variations in size, shape, color and pubescence of plant, leaves and infloresence
(Tithymalopsis Ipecacuanhae, Small). Ipecac Spurge. Only the forking infloresence (3-6 in.) above ground, with its red or green glabrous, opposite leaves varying from oval to linear on different plants, the alternate leaves of the short stem usually subterranean and scale-like: cyathia long peduncled; appendages of glands rudimentary. April. Sandy soil E. U.S. L.B.C. 12: 1145. B.M. 1494. - E. geniculata, Ort., is sometimes cult, under this name. It is a plant of tropical Amer., related to E. heter-ophylla, but with broader leaves the upper whitish at base.
cc. Plant a shrub.