The point in spring when buds on trees and plants begin to open and grow new leaves, signaling the start of the growing season.
From English 'bud' (the unopened flower or leaf cluster) combined with 'break' (to open or split). The term emerged as horticultural vocabulary describing the natural cycle of trees.
Farmers and gardeners have gotten really sophisticated about predicting budbreak using temperature data, because if a late frost hits after budbreak, it can destroy an entire year's fruit crop—making this simple word matter enormously to agriculture.
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