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.
(Caragan, its Mongolian name). Legu-mindsae. Pea Tree. Ornamental shrubs chiefly grown for their bright yellow flowers; some species are also used for hedges.
Leaves abruptly pinnate, often with persistent spiny-pointed rachis; leaflets small, entire; stipules deciduous or persistent and spiny: flowers papilionaceous; standard upright, like the wings with long claws; keel obtuse and straight; stamens 10, 9 connate, 1 free; ovary scarcely stipitate: pod linear, terete, straight, 2-valved, with several seeds. -More than 50 species from S. Russia to China, most of them in Cent. Asia. Mono-: graph by Komarov in Act. Hort. Petrop. 29:179-388 (1908), with 16 plates.
The caraganas are deciduous unarmed or spiny shrubs with yellow, rarely whitish or pinkish flowers axillary and solitary or fascicled, followed by linear pods. The cultivated species are quite hardy, except a few Himalayan species. They grow in almost any soil, but best in a sandy soil and sunny position, and are well adapted for shrubberies. C. arborescens is the only one which grows into a small tree, and is of upright habit, like C. frutex, which is about half as high and more graceful; most of the other species are low shrubs, of usually spreading habit. C. arborescens is one of the best hedge shrubs for the prairies of the Northwest.
Propagation is by seeds sown in fall or in spring; if kept dry during the winter, soaking in tepid water for two or three days before sowing will be of advantage; also increased by root-cuttings and layers, or by grafting on seedling stock of C. arborescens in spring.
a. leaflets 12-18, 1/6-1/2 in. long: rachis deciduous.
Lam. (C.Altagana, Poir. C. arborescens variety arenaria, Hort.). Fig. 790. From 4-6 ft.: leaflets 12-18, obovate, pubescent when young, grayish green, 1/3in. long or shorter: flowers 1 or 2, yellow, 3/4in. long; pedicel about as long as the flower Siberia, China. L.B. C. 11:1064. - Under this name a dwarf form of C. arborescens is often cultivated variety megalantha, Schneid. leaflets bright green, 1/3 or sometimes 1/2in. long: flowers 1 1/4 in. long.
Fig. 790. Caragana microphylla. (X 1/2) bb. Rachis persistent, spiny: pedicels shorter than the flowers
aa. leaflets 8-14,1/2-1 in. long: rachis deciduous. arborescens, Lam. Shrub or small tree, to 20 ft.: leaflets 8-12, obovate or oblong, sparsely pubescent beneath or glabrous at length: flowers 2-4, pale or bright yellow, 3/4in. long; pedicels usually longer than the flowers: pods about 2 in. long. May, June. Siberia, Manchuria. G.O. H.67. variety pendula, Dipp., with pendulous branches, is the most remarkable; it should be grafted high. M.D. G. 1897:425. variety Lorbergii, Koehne. leaflets linear to linear-oblanceolate, about 1 in. long. A very peculiar and striking form.
Bess. (C. Redowskii, Fisch. C. arborescens variety arenaria, Sims). Shrub, to 6 ft., very similar to the preceding: leaflets 10-14, oblong-elliptic to obovate, cu-neate at the base, rounded at the apex; stipules herbaceous or somewhat spiny; pedicels and calyx puberu-lous, calyx-teeth very short: pods about 1 in. long; seeds brown. Amurland, Korea. B.M. 1886 (not good).
AAA. leaflets 2-4.
b. Rachis of the Ivs. deciduous: pedicels as long as or longer than the flowers
Koch (C. frutescens, DC). Fig. 791. From 6-10 ft.: leaflets 4, approximate, nearly digitate, cuneate, obovate or oblong, rounded or emarginate at the apex, glabrous, 1/3 - 1 in. long: flowers solitary, 3/4- l in. long, yellow. May. S. Russia to China. Gt. 10:348. S.B.F.G. 3:227. variety grandiflora, Koehne. Flowers somewhat longer than 1 in.: leaflets usually large and broad. variety latifolia, Schneid. (variety obtusifolia, Hort.). leaflets more than an inch long and about 1/2 in. broad: flowers as in the type.
Fig. 791. Caragana frutex. (X 1/2)
Chamlagu, Lam. Shrub, 2-4 ft.: spines long: leaflets 4, in 2 somewhat remote pairs, chartaceous, obovate, emarginate or rounded at the apex, glabrous, 1/4- 3/4in. long: flowers solitary, reddish yellow, 1 1/4 in. long. May. N. China. G.O.H. 30.
DC. (C. gracilis, Hort.). One to 3 ft.: spines short, 1/4 in.: leaves nearly sessile; leaflets 4, approximate and almost digitate, cuneate, linear-elliptic or linear-lanceolate, glabrous, 1/3-1/2in. long: flowers solitary, 3/4in. long, golden yellow. Caucasus to Siberia and Thibet. B.R. 12:1021. - Grafted high on C. arborescens, it forms a graceful standard tree, with pendulous branches.
C. Altagana, Poir.=C. microphylla. - C. arborescens arenaria, Hort.=C. microphylla. -C. arenaria, Dipp.=C. aurantiaca, Koehne. -C. aurantiaca, Koehne. Allied to C. pygmaea. Flowers orange-yellow; calyx as long as broad; ovary glabrous. Siberia. - C. Boisii, Schneid. (C. microphylla variety crasse-aculeata, Bois). Allied to C. arborescens. Shrub, to 6 ft.: leaflets 10-12, obovate or narrowly obovate, about 1/2in. long, silky pubescent beneath at least when young, whitish beneath; stipules spiny: flowers solitary. W. China. V.F. 57. - C. brevispina, Royle (C.triflora,Lindl.). Spines 2-3 in. long: leaflets 12-16, pubescent: flowers 2-4, on a common peduncle. Himalayas. P.F.G. 2: 184. - C. decorticans, Hemsl. Allied to C. microphylla. Shrub or small tree, spiny: leaflets 8-12, oval, less than 1/2in. long: flowers 1-2. Afghanistan. H.I. 18:1725. - C. frutiscens, DC. =C. frutex. - C. Gerardiana, Royle. Spines 1 1/2-2 in. long: stipules large, scarious: leaflets 8-12, densely pubescent: flowers 1-2, short-pedicelled. Himalayas. - C. gracilis, Hort.=C. pygmaea. - C. grandiflora, DC. Allied to C. pygmaea. leaflets cuneate-oblong, glabrous or pubescent: flowers 1 1/4 in. long; calyx gibbous at the base.
Caucasus. - The plant sometimes cult, under this name is a variety of C. frutex. - C. jubata, Pall. Sparingly branched shrub with very thick, spiny and villous branches: stipules large, scarious: leaflets 8-14, linear-oblong, villous beneath: flowers whitish, 1 in. long, short-pedicelled. Siberia. F.S. 19:2013. L.B.C. 6:522. Gt. 10:331. A very distinct and curious-looking species: hardy. - C. sophoraefolia, Bess. (C. arborescens x C. microphylla. C. cuneifolia, Dipp.). leaflets usually 12, oblong to elliptic, cuneate, acute: pods 3/4in. long. Garden origin. - C. spinosa, DC. Spines 1 in. long: leaflets 4, rarely more, approximate, cuneate-lancec-late, glabrous: flowers solitary, short-pedicelled. Siberia. - C. spinosis-sima, C. Koch=C. spinosa. - C. tragacanthoides, Poir. Spiny: leaflets 4-8, cuneate, oblong, pubescent: flowers solitary, short-pedicelled; calyx villous-pubescent. Himalayas. - C. triflora, Lindl.=C. brevispina. -C. vulgaris, Hort.=C. arborescens. Alfred Rehder.