There is no denying that peonies (or Paeonia, the only genus in the family Paeoniceae,) are superstars of the early summer garden. Showy, fragrant, and a great cut flower, peonies, an herbaceous perennial, are very hardy and easy to grow in zones 3-8. Although relatively maintenance free, here are some helpful tips to help you grow the best peony on your block.
First of all, know this:
When peonies are at their peak and looking their very best, a punishing thunderstorm is going to roll through and ruin the show. Just accept it. It happens every single year and there is nothing you can do about it.
Even without a heavy rain, peonies can get top heavy and tend to droop over. You can give them a little help. Peonies enjoy being supported with a hoop-type support. Put out the support as soon as you see growth, and the leaves will cover the supporting structure in no time. If, however, your new plant is already two feet or higher, wait until next year. You don’t want to break your plant.
Thankfully, peonies have relatively few diseases. The most common one is botrytis. An excellent resource on the diseases of peonies can be found on the Penn State website.
Most likely, you are going to see ants on your peonies, maybe lots of them. Don’t worry about this one bit — it’s natural. Some think they even play a role in helping them flower and will disappear after the plant has done so. There’s no need to spray to get rid of them. They’ll disappear when the blooms open and will do nothing to hurt them (or you.)
Don’t be afraid to cut your peonies and bring them inside (especially if you know that thunderstorm is on the horizon!).
When you do cut blooms, leave at least two leaf nodes on the stem. Your plant needs its leaves to continue to produce food for the plant, so cut your vase display with short stems. After your blooms disappear, your peony plant will continue to please as a leafy bush. At the end of the growing season, cut your peony down to the ground, being sure not to cut the buds. Mulch heavily, and gently remove the mulch in the spring.
If you don’t already have peonies in your garden:
The best way to get this show is to purchase and plant a potted peony right now (spring.) Plant it in a well-drained area in full sun so that the soil level of the potted plant is level with the soil you are planting it in. A soil pH of 6 to 7, but no lower than 5.5 is ideal. Do not fertilize the first year. For that matter, peonies really do not require much fertilizing at all, and over-fertilizing will weaken the leaves and produce small blooms. Too much nitrogen may inhibit bloom growth and encourage more greenery. That said, no fertilizing is better than too much. When you dig your hole, you may add bone meal or compost or superphosphate to the hole, but cover this with soil before you put the plant in, as you may burn the roots otherwise. After the first year, peonies might like a light fertilizing, ¼ to ½ cup of 5-10-10 scratched lightly into the soil at the beginning of spring, and again halfway through the growing season. Do this at the drip line and don’t dig too deeply, as you don’t want to disturb the roots.
The best way to propagate peonies:
This is done by root division, which you do in October when the plant has begun to go dormant. You may cut through the plant while it is still in the ground, and either remove the whole plant and replant parts or just remove some parts. The best time to prepare your new site is in the spring. Dig a hole at least one foot deep or more and add organic matter to the soil. Add 1/4 to 1/2 cup of 10-10-10 per plant to the soil in the bottom of the bed. Do not add fertilizer to the soil that will touch the roots. Add soil back into hole and mark it so you can find it easily. When you are ready to plant, dig a foot-deep hole in your prepared soil area. Make the hole wide enough so the roots can spread out. Place your new plant with at least five eyes so that the eyes are no lower than two inches below the soil level. Planting them too deeply will inhibit blooms next year. If you don’t mind how it looks, you can place your supports in the ground at the fall planting time. It may take up to three years for your new plant to establish and bloom, but it will be well worth the wait.
An excellent resource on peonies this author found is here.