Azaleas /əˈzeɪliə/ are flowering shrubs in the genus Rhododendron, particularly the former sections Tsutsuji (evergreen) and Pentanthera (deciduous). Azaleas bloom in the spring (May and June in the temperate Northern Hemisphere), their flowers often lasting several weeks. Shade tolerant, they prefer living near or under trees. They are part of the family Ericaceae. Azaleas /əˈzeɪliə/ are flowering shrubs in the genus Rhododendron, particularly the former sections Tsutsuji (evergreen) and Pentanthera (deciduous). Azaleas bloom in the spring (May and June in the temperate Northern Hemisphere), their flowers often lasting several weeks. Shade tolerant, they prefer living near or under trees. They are part of the family Ericaceae. Plant enthusiasts have selectively bred azaleas for hundreds of years. This human selection has produced over 10,000 different cultivars which are propagated by cuttings. Azalea seeds can also be collected and germinated. Azaleas are generally slow-growing and do best in well-drained acidic soil (4.5–6.0 pH). Fertilizer needs are low. Some species need regular pruning.