The Mock Orange tree (Philadelphus) blooms with lightly fragrant, white flowers during the middle of spring through early summer. A bright, sunny location in alkaline soil in U.S. hardiness zones 4 through 8 provides the ideal growing conditions for this perennial and ornamental evergreen tree. Flowers bloom from the previous year's branches. Annual hard pruning encourages new growth for increased flower production.
Wait to prune a Mock Orange tree until all the tree's flowers have bloomed and slightly wilted. Do not prune the Mock Orange tree after the last day of July, since the tree goes into dormancy in August, advises the Garden Seeker.
Hold freshly sharpened pruning shears at a 45-degree angle to each tree branch for cutting. Prune one-third of each currently flowering branch. The tree may look a little thin, but new growth comes back for next year's blossoms.
Cut one-third of the old branches out of the Mock Orange. Prune them close to the tree trunk. Old branches are thicker in diameter and harder in texture than the current year's new growth.
Water the base of the tree with 1 to 3 inches of water (until the ground is wet, but not soggy).
Prune your Mock Orange tree every year. Yearly pruning increases plant bloom volume and encourages new growth, according to the University of Illinois Extension and the Garden Seeker. Gardeners sometimes feel they are butchering the Mock Orange by pruning it, until they see the new growth shoots and increased bloom volume the following year.