Use the shovel to dig a planting hole twice as wide as the quince’s original nursery container and at least as deep. Choose an area of the garden that gets full sun to light, partial shade, and has well-drained, moderately fertile soil. Smyrna quince grows well in soil that ranges from acidic to neutral.
Remove the plant from its nursery container and set it in the center of the planting hole. Gently spread the roots out from the root ball with your fingers. Backfill with the excavated soil until the hole is about half full and the soil holds the plant securely. Water the site and wait for the soil to absorb the water. This eliminates air pockets.
Finish filling the hole with enough dirt to make it level with the surrounding soil. Water the plant thoroughly.
Spread mulch 1 to 3 inches deep around the quince, but not touching the main stem. Water the plant thoroughly. Use an organic mulch like bark chips to keep the roots cool and moist.
Water the newly planted Smyrna quince every week or two until the plant is firmly established in the garden. Smyrna is heat and drought tolerant and generally gets the moisture it needs from rainfall. Provide supplemental water during prolonged dry periods or if the soil dries out to several inches deep and the plant seems to be in distress.
Fertilize annually in spring with a slow-release, balanced fertilizer such as 10-10-10. Fertilizer labeled for pears and apples is suitable for quince. Apply 1/2 to 1 cup of fertilizer, or 1 tbsp. of fertilizer per foot of tree height. Spread the fertilizer around the root zone, but not on the main stem, and water thoroughly.
Prune Smyrna quince in winter, during its dormant period. Prune dead wood and thin branches that become tangled or rub against one another.