RHODODENDRON 



RHODODENDRON 



2933 



small selection of them: Balsamin&florum, with double 

 pink flowers (Gt. 37, p. 265. G.C. II. 18:230; III. 

 12:769. J.H. III. 43:151. G.Z. 27:241); Balsaminse- 

 florum album, with double white flowers (Gn.W. 5:373); 

 Balsaminseflorum aureum, with double yellow flowers; 

 Brilliant, brilliant scarlet; Ceres, tawny yellow (Gn. 

 41:845); Diadem, orange-scarlet; Duchess of Conna ught, 

 vermilion-red; Duchess of Edinburgh, scarlet with 

 orange-crimson (F.M. 1874:115); Eos, scarlet-carmine 

 (G.C. III. 19:327); Exquisite, large light fawn-yellow 

 flowers (Gn. 56:62); Favorite, satiny rose; Jasmini- 

 florum carminaium, deep carmine (Gn. 41:328); Little 

 Beauty, flowers small, but bright carmine-scarlet (Gn. 

 5(1:242); Lord Woheley, bright orange-yellow, tinted 

 with rose at the margins; Lutto-roseum, flowers satiny 

 rose, suffused with white, center light yellow (G. 33: 

 313); Maiden's Blush, blush, with yellowish eye (Gn. 

 16:394); Princess Alexandra, white, faintly blushed; 

 Princess Frederica, yellow, faintly edged rose; Princess 

 Royal, pink; Rosy Morn, bright pink (Gn. 42:164); 

 Taylori, bright pink, with white tube (F. M. 1877:242); 

 Triumphans, crimson-scarlet. 



Propagation. All rhododendrons are easily propa- 

 gated by seeds, which are very small and are sown in 

 spring in pans or boxes well drained and filled with 

 sandy peat. Pots should be well watered previous to 

 sowing. The seeds should be covered only a very little 

 with fine sand or finely cut sphagnum, or merely pressed 

 in and not covered at all. To prevent drying, a glass 

 plate may be placed over the pan or some moss spread 

 over the surface; this, however, must be taken off as 

 soon as the seeds begin to germinate. The seeds also 

 germinate very readily if sown on fresh sphagnum, but 

 in this case they must be pricked off as soon as they can 

 be handled. In any case, it is of advantage to prick off 

 the young seedlings as soon as possible, but if they are 

 not sown too thickly they may remain in the seed-boxes 

 until the following spring. The seedlings of hardy rho- 

 dodendrons should be placed in coolframes and grad- 

 ually hardened off; those of greenhouse species remain 

 under glass. Rhododendrons are also sometimes 

 increased under glass by cuttings of half-ripe wood 

 taken with a heel, and if gentle bottom heat can.be 

 given after callusing it will be of advantage. They root, 

 however, but slowly, except those of the Javanese 

 kinds, which are mostly propagated in this way, since 

 they grow very readily from cuttings. Layering is 

 sometimes practised, especially with the dwarf and 

 small-leaved species, but the layers usually cannot be 

 separated untU the second year. For the propagation 

 of the numerous varieties and hybrids of hardy and half- 

 hardy rhododendrons grafting is most extensively 

 employed. R. catawbiense or seedlings of any of its 

 hardy hybrids may be used as stock; R. maximum is 

 also probably as good. In English and Belgian nur- 

 series R. ponticum, which is inferior in hardiness, is 

 mostly employed as a stock, but this often proves fatal 

 if the grafted plants are transferred to colder climates. 

 R. arboreum may be used for strong-growing varieties 

 intended for cultivation in the greenhouse or South. 

 Veneer- or side-grafting is mostly practised, and some- 

 times cleft- and saddle-grafting (see G.C. III. 24:425 

 and Figs. 3380, 3381). The leaves should be removed 

 only partly and the stock not headed back until the 

 following year. The grafting is usually done late in 

 summer or early in spring in the greenhouse on potted 

 stock without using grafting-wax, and the grafted plants 

 kept close and shaded until the union has been com- 

 pleted. If large quantities are to be handled the plants 

 are sometimes not potted, but taken with a sufficient 

 ball of earth, packed close together and covered with 

 moss. Covering with moss to keep the atmosphere moist 

 is also of much advantage if the plants are potted. 



Other experience with the evergreen rhododendrons. (B. 

 M. Watson.) Rhododendrons, in this article, mean 

 more particularly R. maximum and the hybrid varie- 



ties of R. catawbiense; in the main, however, the direc- 

 tions for the various operations apply to the azalea 

 group and to many other members of the heath 

 family. 



Rhododendrons as a class are increased by seeds, 

 layers and grafts, and occasionally by cuttings. Seeds 

 should be sown under glass, between January 1 and 

 March 15, in soil one-half peat and one-half pure fine 

 sand, with good drainage. The seeds are small and 



3380. Grafting of rhododendron. Saddle-graft at A; 

 veneer-graft at B. 



require no covering, the usual watering after sowing 

 being quite sufficient. A thin layer of sphagnum over 

 the surface of the seed-pan is good protection from the 

 sun and keeps the soil evenly moist; it should be 

 removed when germination begins. Seeds may also be 

 sown on growing sphagnum, a thin layer being com- 

 pactly spread above the seed-soil and drainage, and an 

 even surface being secured by clipping. Seed-pans or 

 flats of convenient size are used and they should be 

 plunged in sphagnum still further to insure even moist- 

 ure; the temperature of the house should be 45 to 50 

 F. Seedlings are prone to damp-off and should be 

 pricked off into fresh soil as soon as they are big 

 enough to handle; wooden pincers, made from a barrel 

 hoop, are handy for this work. They are slow growers, 

 and must be tended carefully. Keep under glass, well 

 shaded until the weather is settled. Frames with lath 

 screens make good summer quarters. Winter in pits 

 and plant out in frames in peaty soil when large enough. 

 Never let them suffer from dryness. It has been sug- 

 gested that the seed of R. maximum might be planted 

 on living moss under high-branched trees in swamps 

 where the water does not collect in winter. (See Jack- 

 son Dawson, on the "Propagation of Trees and Shrubs 

 from Seeds," in Transactions of the Massachusetts 

 Horticultural Society, 1885, part I, page 145.) Layers 

 probably make the best plants, and in the best English 

 nurseries layering is the common method of propagation. 

 In the United States layering in spring is preferable, 

 but abroad it is practised in both spring and autumn. 

 It is a slow process, but desirable for the hardy hybrids 

 of R. catawbiense. Roots form on wood of almost any 

 age; when removed the layers should be treated as 

 rooted cuttings and carefully grown in well-prepared 

 soil where water and shade are easily furnished. See 

 Layering. See, also, G.F. 6:63 (1893) for an interesting 

 account of layering large plants by burying them to the 

 top. Grafting is the common method of propagation, 

 and is employed almost universally in continental 

 nurseries. R. ponticum is the usual stock, a free grower 

 and readily obtained from seeds. Attempts have been 

 made to use R. maximum in American nurseries, 

 because of the tenderness of R. ponticum, but no great 

 progress has been made. It is asserted that the rate of 

 growth is somewhat slower than that of the hybrids; 

 this seems hardly possible, and it is to be hoped that 

 further experiments will be made. R. ponticum should 



