Growing Rock Garden Plants

Press, Volume CIII, Issue 30347, 24 January 1964, Page 7

Growing Rock Garden Plants

The culture of rock garden plants increases in popularity each year. One of the reasons is the brilliant show that these plants produce at various times of the vear, csjiecially during’ the spring.

Many of these spring flowering plants are easy to grow and in fact many of them can be grown without a rock garden, although most are seen to best advantage when they cascade over rocks.

After these spring flowering plants have flowered they produce a crop of new growth. When flow’ering has finished the plants should be trimmed to keep them tidy, compact and floriferous. The growths, when they are cut off, can be used for propagation. The trimming should be carried out when the new growths are about an inch in length. Propagation is by cuttings whch are made in the normal way. Young growth is selected and the basal cut is made just below a leaf, the lower leaves should be removed just sufficient to allow insertion of the cutting into the rooting medium.

No special structure is necessary to root the cutting; depending on the number of cuttings a pot. box or cold frame can be used. A rooting medium consists of soil

to which an equal quantity of sharp sand has been added.

If the cuttings are inserted in a pot they should be lined out around its edge using a finely pointed stick and then the pot is watered and covered by a jam jar, or placed in a plastic bag. Where a box is being used, the cuttings are spaced out

about an inch apart, labelled, watered and the box covered either with a sheet of glass, or polythene. If cuttings are to be inserted in a frame the surface of the soil should be covered with a layer of sharp sand about half an inch in depth and the cuttings inserted into this. Water, and cover the frame. Kept From Sun The container with the cuttings should be kept moist and protected from direct sun either by placing in a shady position or by shading with lime wash or scrim. The length of time taken for the cuttings to root will vary with the different plants but on the average it should be between four and six weeks. Once rooted

the cuttings can be exposed to more light and the lights or coverings removed. When well rooted, the cuttings can be potted individually or allowed to remain until the autumn and then planted out. If the cuttings have been closely spaced it will be advisable to give them more space once rooted otherwise thin spindly plants will be produced. These plants are susceptible to ravages by slugs and so protection should be provided. Some plants that can be propagated in this manner are:—Aubretia, Alyssum saxatile, alpine phlox, arabis, sedums, Lithospermum diffusum, Iberis, Dianthus, armeria, Rosmarinus lavandulaceus, Aethionema and spring and winter flowering heaths.