Whether they are growing in a garden bed or as potted plants indoors, geraniums benefit from minor pruning. Geraniums have a tendency to become leggy---some stems grow longer and the plant looses its full ad bushy appearance. Pruning inhibits the legginess and allows the plant to fill out so it is full and lush. This leads to more blooms and a generally more attractive plant. The small amount of time spent pruning will keep your geraniums looking good for many months.
Remove flowers as they whither and the petals begin dying. Cut them off ¼ inch beneath the flower head using a pair of sharp shears.
Cut off any damaged leaves from the plant where they join the main stem. Cut off damaged stems beneath the damaged area.
Remove dying leaves and old stems during winter as the plant begins to produce new growth. Old stems are woody while fresh stems are pliable and green. Cut off the old stems at the base of the plant.
Cut off all the dying stems after blooming is finished or in mid-March as they begin to set new flower buds. Cut them down to 3 to 5 inches long or to one third their previous height. Discard the removed stems.
Water thoroughly after pruning. Apply a liquid plant fertilizer to encourage lush new growth following label instructions for the specific fertilizer brand.