Mulching feeds the plant and retains moisture
To become really well established, young trees and shrubs should have access to plenty of plant nutrients for the first five or six years. On good, fertile soils, this feeding need only be a 5 centimetre layer of well-rotted manure or compost, topped up in April. This layer provides plant food and retains moisture in the soil. On poorer soils, 30 grams per square metre of general fertiliser or Tree and Shrub Fertiliser should also be applied, in spring.
Be careful not to over-mulch on heavy soils because too much mulch can keep the soil wet and cold and restrict growth. Healthy balanced growth helps the plant to resist diseases and pests, and make an impact on the garden more quickly.
Older trees and shrubs need no fertiliser unless they look unhealthy and need a boost following pest or disease attack. Feeding as mentioned will encourage recovery. Established plants growing in poor hungry soil may fail to provide a good display of flowers or foliage and should be fed every year or every two years.