Pluck the wilting blossoms from the plant with your fingers -- you don't need to use pruning tools. Removing blossoms from the sundrop plant as petals begin to fade, called deadheading, prevents sundrops from going to seed so the flowers keep blooming.
Water sundrops once or twice weekly to maintain medium moisture in the soil during periods of drought so they have enough water to keep producing flowers. Many plants shut down flower production and go into a sort of dormancy to survive prolonged periods of drought. Sundrops can tolerate wet or dry soil, but providing water through drought decreases stress on the plants.
Cut back up to one-third the total height of the plant, using a pair of scissors or shears. Many flowering plants rebloom easily after cutting back the foliage, but reblooming is less common with sundrops. In some cases, sundrops might produce a second flush of blooms, although for a much shorter period than the first round of blooms.
Cut back all flowering stems and wilting or brown leaves, leaving only the basal rosette -- the central cluster of leaves at the center of the plant -- when flower and foliage production stops in late summer or early fall. This allows the plant to focus on storing energy in the roots before its winter dormancy.