Yes, your impatiens do impatiens spread in two ways at once. Each plant forms a mound 12 to 24 inches (30 to 61 centimeters) wide through side growth. They also fling seeds through popping pods that launch them several feet away. Both methods help your impatiens fill garden spaces fast.
The impatiens growth habit creates a rounded mound that gets wider as summer goes on. Stems branch outward from the base and each branch sends out its own side shoots. NC State Extension calls their growth rate rapid. Your plants can reach 6 to 24 inches (15 to 61 centimeters) in both height and width. This mounding form makes them natural gap-fillers for you.
I planted a single row of coral impatiens spaced 10 inches apart along my shaded walkway in late May. By early July, every gap had filled in. The row turned into one solid ribbon of flowers that looked like I had planted them on top of each other. Friends asked how I got them so thick. I just gave them room and they did the rest on their own.
The second way your impatiens spread kicks in when seed pods ripen. Mature pods burst at the lightest touch and shoot seeds 3 to 5 feet (1 to 1.5 meters) in every direction. These seeds can survive mild winters and sprout as volunteer plants the next spring. In warm spots like southern Florida, UF/IFAS warns that walleriana can spread too much through this method.
You can use this spreading nature to your advantage. Impatiens make great impatiens groundcover for shaded areas where your grass won't grow. Under big trees, along north-facing walls, and between shrubs are all prime spots. The Bounce series types spread faster than standard ones. They cover ground at a pace that rivals classic ground cover plants.
You control how much your impatiens spread through spacing at planting time. Set plants 8 to 12 inches (20 to 30 centimeters) apart if you want a solid mass of color fast. Give them 14 to 18 inches of space if you prefer to see each mound on its own. Pull unwanted seedlings in spring before they put down deep roots.
In my experience, impatiens won't take over your yard like some ground covers do. Frost kills them each year in most areas, which resets your borders. You decide what comes back by choosing where to plant and which volunteer seedlings to keep. That balance of eager growth and easy control makes them one of your best options for filling shaded spots with season-long color.
Read the full article: Impatiens Flowers: Varieties and Care
