In late June prune back to shape. After this time, next years' flowerbuds will be forming and further pruning will result in fewer flowers the following Spring. Magnolias are easily ground or air-layered in late spring. Root greenwood cuttings in early summer or semi-ripe cuttings in early Autumn. Magnolias are relatively disease free, yellow leaves are a sign of an alkaline soil, an acid-based feed should help green up the foliage.
Aphids can occasionally be a problem .
The main pests to be aware of are scale insects, particularly around flowering time. Either spray with Malathion before the flowers open or rub off with fingers. Do not spray open flowers with insecticides as they will discolor. The Bonsai Site . All Rights Reserved.