How to Successfully Transplant Your Peonies to Maximize Their Blooms
As perennials go, peonies can be extremely long-lived, growing for up to 100 years. They are deer- and rabbit-resistant too, so you can usually depend on peonies to put on a beautiful spring show with their enormous, colorful flowers. But after 10 or 15 years, peony blooms slow down, and that's the time for you to dig, divide, and transplant them. You can replant a part of your original peony and its divisions in the same part of the garden or find new areas for them. Or you can even share the wealth; peonies make perfect pass-along plants to give to family and friends.
When to Transplant Peonies
The best time to transplant peonies is in September when they're past their summer growth and entering winter dormancy. But it's also possible to dig and plant the entire root ball in the spring before the plants start to sprout new growth for the season. Disturbing peonies at any other time of the year will likely stress them out too much for them to survive.
How to Divide Peonies
First, gently dig up the plant, keeping as many of the roots as possible. You'll pull up a lumpy crown with small, reddish buds (eyes) poking up from it and stringy roots trailing below. Gently shake or wash most of the soil off the roots. If the crown has at least six eyes, you can divide it to energize the peony and get more flowers in the future. Use a spade ($26, Lowe's) with a sharp blade to slice the crown into pieces that have at least three eyes each.
Where to Transplant Peonies
Your peonies will give you the most flowers if they get at least 6 hours of sun every day. In a pinch, you can place them in part shade, but you'll see fewer flowers. As for soil, anything will do as long as it drains well. Don't plant them where the rain puddles in your garden.
Peonies need good airflow around them to prevent powdery mildew, so dig the new holes at least three feet apart. The holes should also be wide enough to provide generous room for new roots to grow. As for depth, peonies are persnickety about being planted close to the surface; the eyes should be only a couple of inches underground or the peony will not bloom. Hold the peony crown to almost surface level and pat the freshly dug soil back in around the peony roots and over the top of the crown.
Caring for New Peony Transplants
After planting, water the divisions thoroughly. Peonies need to be watered weekly until the ground freezes in the fall. If nature doesn't supply weekly rains, you'll need to step in with your trusty garden hose. In November, spread 4-6 inches of mulch over your peonies to keep soil temperatures stable through the winter. In the spring, remove the mulch and either spread it out around your garden beds or add it to your compost pile.
Peonies are known as slow starters, so you likely won't see maximum blooms for 2-3 years. But once they're in gear again, the transplanted peonies will be your garden all-stars for many years to come.