How to Prune little-leaf mock orange?
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune immediately after flowering.

little-leaf mock orange · Philadelphus microphyllus
Also known as: desert syringa
Plant in neutral to alkaline, moderately fertile, moist but well-drained soil in full sun. Can tolerate dryer soils once well established.
Cut flowered growth back to strong young shoots below, removing up to a fifth of old stems near the base each year. Prune immediately after flowering.