50 ROGK GARDENING FOR AMATEURS 



alpines possessing thick fleshy roots, may be increased 

 in this way. 



The process is a simple one, and is best performed 

 during the winter months, from November to February. 

 The usual practice is to cut the roots into pieces about 

 an inch and a half long, more or less, and to put them, 

 with the thicker end up, in pots or boxes of sandy soil, 

 and to place these in a greenhouse or frame. The top 

 of the cutting ought to be just visible on the surface 

 of the soil. In spring the root cuttings will begin to 

 show leaves, and when they have made some growth 

 they should be potted and treated like ordinary cuttings. 



The following is a selection of rock plants commonly 

 increased by division: Acaena. Achillea, Adonis, 

 Anemone, Arabis, Arenaria, Campanula, Cerastium, 

 Dodecatheon, Draba, Erodium, Gentian, Geranium, 

 Geum, Gypsophila, Haberlea, Hutchinsia, Iris, Linnaea, 

 Mentha, Mertensia, Mimulus, Omphalodes, Oxalis, 

 Polygonum, Primula, Ranunculus, Saxifraga, Schizoco- 

 don, Sempervivum, Shortia, Tiarella, and Trillium. 



Chief among those increased by cuttings are: 

 Acantholimon, ^Ethionema, Alyssum. Androsace, An- 

 tirrhinum, Aubrietia, Cistus, Cytisus, Dianthus, Helian- 

 themum, Hypericum, Iberis, Lithospermum, Ononis, 

 Phlox, Potentilla, Saponaria, Sedum, Thymus, Veronica 

 and Viola. 



