Causes of LeggyGeranium Plants. Most leggy growth on geraniums is the result of irregular pruning maintenance.Excessive moisture is another cause of leggygeraniums. Overgrown Geraniums: Preventing And Correcting LeggyGeranium Plants. Many people wonder why their geraniums get leggy, especially if they keep them year after year. Geraniums like full sun. One reason they may become leggy is if they are growing in too much shade, so be sure to situate them in a location where they can bask in the sun. Those scraggly, stretched-out plants can become full again—and the solution for leggy plants may be as simple as tweaking your lighting. She agreed wholeheartedly and into action I sprung to prune the leggy, overgrown geraniums. This guide to low-maintenance geranium care will provide pretty leaves, showy flowers, and long bloom times to your home garden. Before planting outdoors in May, make sure to fertilize them with a dilute fertilizer such as 5-10-5. Iowa State University has an excellent article on Overwintering Geraniums. If you've noticed your geraniums looking tall, leggy, and lacking in blooms, it's time for a makeover. In this article, I'll walk you through the expert pruning techniques that will transform your... Geraniums with the term pillar in their names tend to grow upward more than outward, so "leggy" stems are to be expected. Some varieties reach 18 to 30 inches tall. LeggyGeranium with Long Flower Stems: Quick Fixes. ByArifur Rahman.Sometimes, though, houseplant enthusiasts encounter a problem: their geranium seems to stretch skyward.