Recent research from Cornell University's Flower Bulb Research Program has shown that planting perennial flowers higher in the soil may result in better growth and survival.
"High" planting refers to planting the perennial with buds and crown slightly above the ground. "Deep" planting refers to planting so the buds and crown are about 1 inch below the soil line.
In tests with 24 different perennial flower species, researchers evaluated the survival and root growth six weeks after planting perennials either "high" or "deep" in pots. In almost every case the perennials planted "high" had the same or better root growth and survival rates than those planted "deep." Some perennials, such as geum, showed dramatic results. Only 10 percent of the geums planted "deep" survived, while 85 percent of the Geums planted "high" thrived.
Although this research was done in pots, home gardeners should consider planting their perennials in the garden a little higher than normal -- especially in heavy soil -- to insure the best growth.
For more information on this research, go to the Cornell University Flower Bulb Research Program Web site.