How to Prune small-flowered tamarisk?
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.

small-flowered tamarisk · Tamarix parviflora
Grows well in most soils but dislikes shallow chalky soil. Requires full sun and a well-drained sandy soil in coastal plantings but it requires shelter from cold drying winds when planted inland
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.