RHODODENDRON 



. RHODODENDRON 



1519 



of propagation. With us layering in spring is prefer- 

 able, but abroad it is practiced in both spring and au- 

 tumn. 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 fur- 

 nished. See Layering. See, also, G.P. 6:63 (1893) for 

 an interesting account of layering large plants by bury- 

 ing 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 ex- 

 periments will be made. R. Ponticum should be estab- 

 lished in pots in spring and grafted under glass in 

 autumn and early winter, using the veneer-graft (see 

 Graftage, p. 664, Vol. II). Graft as near the root as 

 possible and plant the worked parts below the surface 

 when planting in the nursery or permanently. With these 

 precautions, and an extra covering of leaves until the 

 plant is established on its own roots, the defect of ten- 

 derness in this stock can be overcome. Nurse carefully 

 the young grafted plants in frames until of sufficient 

 size to be planted in the nursery rows. Figs. 2107 and 

 2108 illustrate two common methods of grafting Rho- 

 dodendrons and other woody plants. The details of the 

 unions are shown in Fig. 2107, and the completed work 

 in Fig. 2108. 



Statements are made that cuttings of half - ripened 

 wood will strike, but it is not likely that this will ever 

 prove a practical method of propagating R, maximum 

 or the Catawbiense hybrids: it might be worth while to 

 experiment with wood grown under glass, particularly 

 with some of the smaller-leaved evergreen kinds. 



Cultivation. The point upon which the successful 

 American growers of Rhododendrons now insist is that 

 the water supply shall be sufficient. See H. H. Hun- 

 newell, in G. F. 3:201 (1890). To effect this: (1) make 

 the soil deep and fine, using materials like peat, leaf- 

 mold, well-rotted manure and yellow loam, all of which 



natural water supply, nor so near buildings that the 

 border is sheltered from rain or overdrained by cellar 

 walls; (5) mulch with leaves summer and winter, pro- 

 tect from wind and sun with evergreen boughs in win- 



2106. A common hybrid form of Garden Rhododendron. 



are retentive of moisture; (2) plant in masses, at any 

 rate while young, so that they may protect each other 

 and prevent evaporation; (3) give the bed a northern 

 exposure or a situation where the force of the midday 

 sun is broken; (4) do not plant under or near trees 

 like elm, oak or maple which make undue inroads on the 



96 



2107. Grafting of Rhododendron. 

 Saddle-graft at A; veneer-graft at B. 



ter and in summer give heavy watering whenever the 

 weather is excessively hot or dry. 



Soil. The bed should be prepared by excavating to 

 the desired dimensions and at least three feet deep. 

 The poor material should be discarded, but the good 

 soil can be replaced, adding enough peat, etc. (see 

 above) to make good that which was rejected: all 

 should be thoroughly and carefully mixed. Peat, al- 

 though excellent, is not necessary. Yellow loam or 

 hazel loam, if not too sandy, is equally good and is im- 

 proved by additions of humus. To nearly pure peat an 

 admixture of sand is beneficial; the essential point is 

 that all soils for these plants must be fine. The beds 

 should be prepared in autumn and left to settle all win- 

 ter, due allowance being made for shrinking. In spring 

 level off to the grade of the adjacent land and do not 

 leave "rounded up." A bed higher at the center than at 

 the sides perhaps makes a better display of the plants, 

 but it is more likely to dry up and does not catch all 

 the water possible from occasional showers. It is gen- 

 erally conceded that lime soils and manures containing 

 lime, e.g., wood ashes and bone meal, are injurious to 

 Rhododendrons; in limestone regions it is undoubtedly 

 advisable to substitute, for the natural soil, others 

 which are free from this objectionable element. 



Planting. Plant in spring when the weather is set- 

 tled and the March winds have passed. If the ball of 

 roots is dry, soak well before setting. Plant 

 closely, so that the tops are only 10-12 in. 

 apart and pay particular attention to "facing" 

 them, i. e., see that the best side is facing 

 the most important point of view and that all 

 are faced alike. Grafted plants should, if pos- 

 sible, have the worked portion below the sur- 

 face. Do not plant in autumn. Plants grown 

 on the premises may be transplanted in favor- 

 able weather in summer if great care is taken 

 to prevent the roots suffering from dryness. In plan- 

 ning the original border it is well to leave room for 

 extension: when planted, as described above, the beds 

 can be enlarged at intervals of four or five years, or 

 new beds made from the old stock. Place the beds so 

 that the glare of the midday sun is screened both sum- 

 mer and winter, and avoid situations where there is 

 any interference, owing to trees or buildings, with a 

 naturally good condition of the soil in respect to mois- 

 ture. If permanent protection is desired, use conifers, 

 oarticularly the hemlock, in preference to deciduous 

 'rees. Good positions for beds may be found along the 

 =idges of ponds and streams, and in reclaimed meadows, 

 with their cool moist soil, but keep aloof from any 

 ground where the water collects in summer or winter. 

 Beds, or even single plants, if sizable, may be intro- 

 duced into open spaces in woodlands if the precautions 

 noted above are observed and plenty of air and light are 

 obtainable. It is somewhat difficult to combine Rhodo- 



