Because in the Fall they “Let It Go” and in the Spring they “turn over a new leaf”.
Interesting Fact:Azaleas/əˈzeɪliə/ are flowering shrubs in the genus Rhododendron, particularly the former sections Tsutsuji (evergreen) and Pentanthera (deciduous). Azaleas bloom in spring, their flowers often lasting several weeks. Shade tolerant, they prefer living near or under trees. They are part of the family Ericaceae.
Interesting Fact: Spring is one of the four conventional temperateseasons, following winter and preceding summer. There are various technical definitions of spring, but local usage of the term varies according to local climate, cultures and customs. When it is spring in the Northern Hemisphere, it will be autumn in the Southern Hemisphere. At the spring equinox, days are approximately 12 hours long with day length increasing as the season progresses. Spring and “springtime” refer to the season, and also to ideas of rebirth, rejuvenation, renewal, resurrection and regrowth. Subtropical and tropical areas have climates better described in terms of other seasons, e.g. dry or wet, monsoonal or cyclonic. Often, cultures have locally defined names for seasons which have little equivalence to the terms originating in Europe. ( https://en.wikipedia.org/wiki/Spring_(season)#Meteorological_reckoning )