Olive trees (Olea europaea) grow slowly and persist in mild-winter climate regions that also have hot, dry summers. The tiny creamy white flowers are fragrant and occur in clusters on branch ends among the leaves. Each blossom reveals four lobes.
Olive trees bloom anytime from mid-spring to early summer. Precise timing depends on local climate. The warmer the temperature, the earlier the flowering commences and it may continue for a few weeks across various branches on the tree.
Research published in the "New Zealand Journal of Crop and Horticultural Science" in 2006 suggests that olive trees bloom best after a cool period in winter. If temperatures remain below 50 degrees Fahrenheit, the return of warmth in spring yields more consistent, widespread flowering all at once across the tree. If winters are too mild, trees bloom slightly later in spring or early summer.
Olive flower buds are already formed by fall on the branches and remain dormant across the winter. Exposure to chilly temperatures primes the buds for final development for flowering sometime in spring.