Perennials: Peonies can be divided and/or transplanted from mid-September to the end of October. First, cut back any remaining foliage close to the ground. Be careful when digging the roots, as they are somewhat brittle. When replanting, look for the small pink “eyes” (the buds) near the top of the roots. This is where the stems will come from next year. If you are dividing peonies, each root should have at least two eyes, preferably three. The roots should be replanted so the eyes are located no deeper than 1½-2 inches below soil grade. One of the primary reasons that peonies don’t bloom is because they are planted too deep, so watch the depth when replanting. Now is also a good time to dig up and divide crowded daffodil, tulip and lily bulbs and re-plant. If your bulbs have formed large colonies but don’t bloom much anymore, it may be due to over-crowding, so division is the cure for that! You may want to use markers or stones to mark where they are planted so you don’t plant annuals or perennials on top of them. Tulips are particularly intolerant of the large quantities of water and fertilizer needed to grow annuals well, so they shouldn’t be planted where you typically put annuals or perennials that need a lot of water. Tulips come from areas of the Middle East such as Iran, Turkey and Iraq that have very hot, dry summers. While tulips like water when they are in flower, they prefer hot, dry conditions when dormant. Hybrid tulips often don’t survive long in our heavy Midwestern clay soils anyway, but some of the “species” of tulips that are shorter in stature often survive much longer, especially in drier areas. Some of these include Tulipa griegii, Tulipa tarda, and Tulipa kaufmanniana. Many bulb companies carry these as well as some local garden centers. These bulbs can survive for a number of years in sunny areas that are dry in summer.
Lisa Johnson, Dane County UW-Extension horticulture educator