Care for a quince tree by growing it in a sunny location and watering it regularly. A quince tree also requires a yearly layer of mulch and fertilizer. Keep an eye out for brown rot, leaf blight and codling moth infestations.
Choose a location for a quince tree that has plenty of direct sunlight so the fruits can ripen thoroughly, preferably on a rise or slope against a south- or west-facing wall. Place a freestanding tree in a location where it can grow up to 12 feet high and 16 feet wide. Dwarf quince trees can be grown in 18- to 24-foot pots. Use well-drained soil amended with organic matter.
After planting the tree, spread a 3-inch layer of mulch on the soil around it to retain moisture. Water the plant often, especially in hot and dry weather, so the soil remains moist. Place a potted quince tree on a stand to improve water drainage.
In the winter, cut back any dead or damaged limbs, and thin out leggy, awkward branches. Watch for leaf spotting, rotting fruit, and signs of leaf blight, brown rot and codling moth. Immediately remove any diseased fruits and branches. Apply fungicide to the tree for leaf blight, and set traps for codling moth infestations.