Flowering quince bushes are deciduous woody shrubs with thorny branches that display flowers from late winter to mid-spring. Infrequently, small edible fruits form during the summer with a hard texture and bitter taste. Japanese flowering quince (Chaenomeles japonica) grows 3-feet tall and wide while the larger common flowering quince (Chaenomeles speciosa) matures 6- to 10-feet high and wide.
Flowering quince bushes attain the most compact, uniform branching and prolific flowering if grown in full-sun conditions, and receive at least six to eight hours of direct sunlight daily. They tolerate partial shade, but the number of flowers decline and shrubs may look lopsided or stunted because of the lack of consistent, intense light during the growing season.
Provide a moist, well-draining garden soil that never floods or becomes soggy after rainfall. An acidic or neural soil (pH below 7.0) ensures foliage never yellows because of a lack of nutrient uptake from the roots. Amend loose sand or heavy clay soils with organic matter to improve drainage and promote healthy growth. Avoid planting in dry soils or where excessive winds lead to wilted, stressed foliage.
Flowering quinces originate in the temperate regions of eastern Asia, where winters are cool to cold. Therefore, grow them in areas rated United States Department of Agriculture (USDA) Hardiness Zones 5 through 8, and perhaps also in Zone 9 where winters reliably dip below 30 degrees Fahrenheit annually. The shrub's flower buds swell readily in the warming days of mid- and late winter and open when the threat of a killing frost remains. Flower petals brown if nipped by late season frosts and freezes.
The natural habit of these shrubs ranges from domed or mounded to upright, rounded and vase-like. Refrain from planting quinces too closely together when young, as it leads to a thicket of many spiny branches and potentially awkwardly shaped plants. Generally, quinces that grow with minimal pruning and clipping attain the most beautiful forms.
Soils that remain consistently moist across the growing season promote best flowering, foliage and potential production of fruits. Natural rainfall or irrigation in the amount of 1 inch every seven to 10 days prevents any leaf yellowing or leaf drop from drought stress. Established plants tolerate some drought without detriment, however.