Unhealthy trees may bear poorly, if at all. Root rots, boring insects, crown galls, oak root fungus and other maladies are almost invisible to the untrained eye, but can put so much pressure on the tree that its fruit is almost completely sacrificed. Tree health begins early, with proper placement in the garden, well-drained soil, full sun and compatible plants nearby. Shade, often caused by overcrowding, reduces flowering and fruiting considerably. Old trees often fruit poorly, due to their lack of vigor and the onset of internal diseases and pests.
Reason No. 5: Poor culture
Cultural practices for good tree health include cultivating or mulching to reduce weed competition for nutrients and water. Fertilize early each spring and summer with an organic fertilizer and mulch as needed. Water deeply and infrequently, soaking the entire root system but keeping the trunk primarily dry, instead of brief frequent bursts from overhead sprinklers.