1620 



HYDRANGEA 



HYDRANGEA 



flowering, the plants are pruned and repotted or planted 

 out and treated as above described for cuttings, or they 

 may be thrown away and another set of jilants raised 

 from cuttings. 



H. petiolaris is a handsome climbing plant for cover- 

 ing walls and trunks of trees, and grows well in the 

 shade, but flowers freely only in the full sun. 



The hydrangeas are readily propagated by cuttings 

 of half-ripened or nearly rijje wood under glass in sum- 

 mer (Fig. 1929); also by hardwood cuttings, layers, 

 suckers or division of older plants. H. guercifolia is 

 be.st propagated by suckers or by layers of growing 

 wood put down in summer. Rarely increased by seeds, 

 which are very small, and should be sown in fall in pans 

 or boxes and only slightlj' covered with soil. 



acuminata, 7 (1). 

 albo-variegata, 7. 

 aUissitmi, 16. 

 anomala, 16. 

 arborescens, 8. 

 aspera, 13. 

 Azisai. 7 {1). 

 Belzonii, 7(1). 

 Bretschneideri, 4, 5 

 Buergeri, 7 (1). 

 cinerea, 9. 

 ^--cardata, 8. 

 cyan^a, 7 (1). 

 cyanoclada 7 (2). 

 Davidii, 6. 

 fimbriata, 7 (3). 

 floribunda, 2. 

 glabrescens, 4. 

 grandiflora, 2, S. 

 heteromalla, 3. 

 Hortensia, 7 (2). 

 hortensis, 2, 7, 14. 

 iuvolucrata, 14, 



japonica, 7 (1). 

 Lindleyana, 7 (1). 

 macrophylla, 13. 

 macrosepala, 7 (1). 

 mandshurica, 7 (2). 

 Mariesi. 7 (1). 

 monstrosa, 7 (2). 

 nigra, 7 (2). 

 nivalis, 7. 

 nivea, 10. 

 opuloides, 7. 

 otaksa, 7 (2). 

 paniculata, 2. 

 pekinensis, 4. 

 petiolaris, 15. ^ 

 plena, 7 (2). 

 praerox, 2. 

 prolifera. 7 (3). 

 pubescetis, 3. 

 guercifolia, 1. 

 radiata, 10. 

 ramuiis, 7 (2). 



rosalba, 7 (1). 

 rosea, 7 (2). 

 roseo-marginata, 7. 

 Rosthornii, 12. 

 rubro-plena, 7 (3). 

 Sargentiana, 11. 

 scanderis, 15. 

 serrata, 4, 7 (1). 

 setcbuenensis, 5. 

 stellata, 7 (3). 

 sterilis, 8, 9. 

 strigosa, 13. 

 tardiva, 2. 

 Thunbcrgii. 7 (1). 

 tricolor, 7. 

 uriicifolia, 8. 

 variegata, 7. 

 Veitchii, 7 (1). 

 vestita, 3, 4, 

 volubilia, 15. 

 Wilsonii, 5. 

 xanthoneura, 5. 



A. Shrubs erect or spreading: stamens 10: petals 



expanding. 



B. Infl. pyramidal. 



1. quercifolia, Bartrara. Shrub, with spreading 

 branches, to 6 ft. : young branches densely ferrugineously 

 tonientose : Ivs. long-petioled, roundish or broadly ovate, 

 pinnatcly lobed with serrate lobes, glabrous above at 

 length, whitish tomentose beneath, 4-8 in. long: 

 panicle 4-7 in. long; fls. pinkish white, the sterile ones 

 turning purple; styles 2: caps, with the calyx-teeth 

 at the apex. June. Ky. to Ala. and Fla. B.M. 975. 

 Gng. 2:.305. Gn.M.2:"66. G.C. 11. 22:369. On. 27, 

 p. 199. G. 27:.389. G.W. 5, p. 109. M.D.G. 1913:517. 



2. paniculata, Sieb. Slirub or small tree, to 30 ft., 

 with dense globose head: Ivs. elliptic or ovate, acumi- 

 nate, serrate, sparingly pubescent above, more densely 

 on the veins beneath, 2-5 in.: panicle 6-12 in. long; fls. 

 whitish, the sterile ones changing later to purplish; 



1930 Hydrangea paniculata var grandiflora. 



styles 3: caps, with the margin of the calyx about at 

 the middle. Aug., Sept. Japan, China. S.Z. 61. F.E. 

 15:501; 34:387. F.R. 21:9. G.W. 2, p. 114; 12, p. 

 366. G.C. III. 9:.5.53. Gn. 59, p. 181; 75, p. 548; 

 76, p. 5. Mn. 9:75. The following varieties are cult.: 

 Var. floribunda, Regel. Panicles large, with more and 

 larger sterile fls. Gt. 16:530. Var. grandiflora, Sieb. 

 (var. hortensis, Maxim.). Fig. 1930. Almost all fls. 

 sterile; panicles very large and showy. F.S. 16:1665, 

 1666. Gn. 10:37; 38, p. 569; 54, p. 376; 64, p. 407; 72, 

 p. 560. R.H. 1873:50; 1899, pp. 130, 131. Mn. 8:119. 

 A.G. 18:313. Gng. 3:3.57; 5:3. F.E. 8:214. S.H. 

 1:174. G.M. 39:728; 46:794. Gn.M. 2:67. A.F. 

 17:194, 517. C.L.A. 7:43. G.W. 8, p. 210; 15, p. 454. 

 G.Z. 10:80. Var. prsecox, Rehd. Fig. 1931. AJmost hke 

 the type, but flowering about 6 weeks earUer, in the 

 middle of July; sepals usually elliptic. G.F. 10:363 

 (adapted in Fig. 1931). The late-flowering typical 

 form is sometimes called var. tardiva, Hort. — H. 

 paniculata var. grandiflora is the common hydrangea of 

 lawns. It is seen to best effect when planted close in 

 front of heavy shrubbery. Cut back rather heavily 

 in early spring. 



BB. Infl. corymbose, flat or globular, 



C. Ovary partly superior, hence caps, ovoid, with the 

 margin of the calyx about the middle; styles usually 

 S: sterile fls. present. 



D. Fertile fls. xohite. 

 E. Lvs. white-tomentose below. 



3. heteromalla, Don (H. vestita, Wall. H. pubes- 

 cens, Decne.). Shrub, to 10 ft.: petiole deeply grooved 

 and margined, red; lvs. ovate, acuminate, densely 

 setosely dentate, almost glabrous above, densely 

 whitish-tomentose beneath, 4—8 in. long: cjine 5-S in. 

 broad, with bracts; sepals of sterile fls. elliptic or 

 obovate, acute or mucronulate: caps, with the calyx 

 above the middle. June, July. Himalayas. F.S. 

 4:378—79. G.C. II. 22:617. G.M. 50:859. 



EE. Lvs. villous or nearly glabrous below. 



4. Bretschneideri, Dipp. {H. vesCUa var. pubescens, 

 Maxim. H. pekinensis, Hort.). Fig. 1932. Slirub, to 

 8 ft.: last year's branchlets with chestnut-brown bark 

 peehng off in thin flakes: petioles not margined; lvs. 

 ovate or elliptic-ovate to oblong-ovate, acute or acumi- 

 nate, serrate with short callous teeth, more or less 

 pubescent beneath, 3-5 in. long: cymes similar to the 

 former but smaller and denser; sepals roundish, obtuse: 

 caps, with the calyx near the middle. July. N. China. 

 G.F. 3:17 (adapted in Fig. 1932); 6:396. G. 27:387. 

 Gng. 16:305. G.W. 9, p. 541. Var. glabrescens, Rehd. 

 (//. serrata, Koehne, not DC). Lvs. smaller, elliptic, 

 more coarsely serrate and only sparingly pubescent. 



5. xanthone&ra, Diels. Shrub, to 15 ft.: last year's 

 branchlets with close chestnut-brown bark marked 

 with conspicuous lenticels: lvs. elhptic to elliptic- 

 oblong, abruptly acuminate, serrate, glabrous 

 and bright green above, marked with more or 

 less conspicuous yellow veins, hght green below 

 and glabrous or slightly pubescent on the veins, 

 4-7 in. long; petioles 3-^-lJ4 in. long: corymbs 

 rather loose, convex, 5-10 in. across; sterile fls. 

 1 'i-2 in. across, with oval obtuse sepals. July. 

 W. China. Var. Wflsonii, Rehd. Last year's 

 branchlets grayish or pale brown: lvs. somewhat 

 narrower, glossy above. W. China. M.D.G. 

 1912:26. The handsomest form of the species. 

 Var. setchuenensis, Rehd. (H. Bretschneideri 

 var. selchienensis, Rehd.). Last year's branch- 

 lets hght brown: lvs. to 8 in. long and to 4 in. 

 broad, villous below. W. China. — This species 

 and its varieties have proved hardy at the Arnold 

 Arboretum. It is very similar to the preceding spe- 

 cies, but easily distinguished by the close bark. 



