Think it is difficult looking after an Acer? Think again!
Acid or Alkaline?
All maples will grow in acid soil but not all will grow in chalky or alkaline soils. The list is too complex to go into here but despite popular thoughts- Acer palmatum varieties seem to do as well in the acid soil as alkaline or broadly neutral soils. Many Acers we have planted have thrived in clay soil... water and sunshine (like us!) are their only true requirements.
Most maples are perfectly hardy even if the new growth on Acer palmatum varieties is not. The Acer is known for its strength and rigour. Please see hardiness on individual descriptors for specific species.
Cool dappled shade with shelter from cold north and east winds or westerly gales is what most Acers prefer. The new growth is especially tender on Acer palmatum varieties (and emerges very early in the year) It is best to avoid frost pockets and try to also avoid the full sun all day, at least as far as Acer palmatum varieties are concerned. Variegated foliaged Acers need the most care. The afternoon sun will simply scorch the leaves. If this happens to a young plant it is best to dig the plant up and take it into the greenhouse to let it recover under the bench in the partial shade. Acer palmatum ‘Ukigumo’ and the other variegated Acer palmatum varieties such as ‘Butterflies’ are particularly prone to scorching and should always be grown in shade.
In an ideal situation, Acer palmatum should have a slightly acidic, sandy, well-drained soil that does not dry out in summer or become waterlogged in winter. Acers have shallow fibrous root systems which benefit from an annual mulch of organic matter. This also helps avoid wilt.
Acer palmatum varieties adapt well to life in a pot providing the roots are kept moist and have good drainage and aeration. Crocks in the bottom of the pots are a good idea. Melcourt peat-free multipurpose compost plus added John Innes is best together with bark mulch to help avoid water loss. Watering depends on the size of the pot or plant and the weather. It is crucial to keep even soil moisture but the roost must not become soggy and waterlogged. Maples need good drainage. Feed with a balanced proprietary fertilizer in spring just as the leaves emerge. Additional Mycorrhiza Root Enlarger will give your plant the best possible start.
Repot every 3 – 4 years in spring well before the first new growth emerges, - this means effectively in February or early March.
If pruning is undertaken it should only be done to improve their overall shape and to encourage healthy growth. Young Japanese maples, for instance, often produce single new shoots in one direction which, if not cut back, will grow on to create an unbalanced plant. Maples require a good leading shoot. Species such as Acer davidii often lose their leader and produce two side shoots instead. It is best to cut out one of these side shoots so that the other will become the new leader. Pruning is best carried out when the sap is falling in late summer or autumn, but generally in the nursery, if an Acer needs a gentle prune, this can be done in any month to no harmful effect.