Peonies bloom at the peak of spring and provide stunning floral displays in the garden and fresh cut flowers when brought indoors. They are long-lived, low-maintenance, and fairly fast-growing in full sun or light shade. Peonies also attract butterflies and are deer and rabbit resistant!
Herbaceous Peonies
Herbaceous peonies have been around for a long time, planted and loved by gardeners for generations. Their burgundy-colored foliage emerges from bare ground each spring and quickly grows to about 2 to 3 feet tall with large, showy flowers at the ends of almost every stem; many varieties are also fragrant.
Blossoms can be heavy and may weigh down the stems if not provided with a cage or other support. Flowers may be frilly doubles, semi-double, or singles, mostly in pastel hues, but colors vary by cultivar. Overall, they have a relatively short yet glorious flowering time and do not tend to rebloom. ‘Karl Rosenfield’ has enormous, cherry-red flowers with a sweet aroma and is widely considered a garden classic.
Itoh Peonies
Itoh peonies are a newer introduction, and a cross between herbaceous peonies and tree peonies. They were the result of a lifetime of work done by Japanese botanist Dr. Toichi. The result is a magnificent, fast-growing plant with huge flowers held on strong stems with attractive foliage; they generally do not require staking or support and are resistant to blight.
Itoh’s growth habit is a bit wider than tall; mature plants grow to about 2½ feet tall by around 3½ feet wide, and they usually begin to bloom in early June, just as the herbaceous peonies are finishing their flower display. Hardy to Zones 4–8, the plants do well in full sun or partial shade and die back in winter, leaving a short, woody stem above ground. Mature plants can have up to 50+ flowers in one season, and flowers may grow to dinner plate size. Plants can often produce a light, second flowering if deadheaded.
Although originally only available in yellow, Itoh peonies now come in a wide range of colors including coral, red, pink, and white. They can be grown for a few years in a container (at least 18 inches tall and wide; add pumice for extra drainage), but are ultimately best grown in the ground. ‘Bartzella’ has bright yellow, double flowers with a spicy scent and features brilliant fall color.
Ants & Peony Flowers
As peony flower buds mature, a sweet, sticky substance appears on the bud surface and can be attractive to ants. Gardening folklore tells us that the ants help the flowers open by “tickling” the buds and removing the sticky sap, but this is not exactly true. Although the ants are certainly not doing any damage to the plant, the flower would most likely open without their assistance. The ants do provide a benefit to the plant, however, by defending it against pest insects, and in reward, are able to access a food source from the secretions of the flower bud.
To avoid bringing ants inside on cut peony flowers, cut blooms in early morning while plants are covered with dew and ants are not yet present, or turn cut flowers upside down and gently tap them with your fingers to dislodge unwanted “guests” before bringing them indoors. Cut flowers can also be quickly submerged into a bowl of water to remove hidden insects from inside blooms.
Planting
The ideal time for planting peonies is in the fall—September to October. Plant in full sun or light shade with rich, well-draining soil. Keep a newly purchased plant in its pot through spring and summer, and protect it from damage by sinking the container into the ground in place until fall planting time arrives.
1. As the plant begins to go dormant in the fall, remove the plant from the ground and dig the hole about twice as wide as the root ball. Fill the hole with water to check drainage then add granular, organic, all-purpose fertilizer and/or bone meal.
2. Remove plant from pot and loosen roots as needed before placing in planting hole. Be watchful of the planting level; ensure that the buds or “eyes” are no more than 2 inches below the top soil level when planted—peonies may fail to bloom if buried too deeply.
3. Backfill hole with blend of native soil and compost or rotted manure; water well to settle the soil.
Feeding Peonies
If peonies are grown in rich, fertile soil, they may not need regular feeding, but in general, established herbaceous peonies can be given a top dressing of granular, organic, all-purpose fertilizer (4-4-4) each spring as new growth begins. Itoh peonies, however, are known to be sensitive to nitrogen, so they should be given a fertilizer that has a low first number on the label, such as 4-6-3 G&B Tomato, Vegetable & Herb or 3-7-4 G&B Bud & Bloom.
Pruning Peonies
Both types of peonies will die back during winter and should have old foliage removed annually to avoid spreading disease. Herbaceous peonies can be cut to the ground as the foliage turns brown in late fall. Itoh peonies should be pruned back to leave a 4 to 5-inch woody stem above ground in late fall; may need to be lightly pruned the following spring as new growth emerges. Standard tree peonies are generally not pruned at all. Dividing and transplanting is best done in fall.
Troubleshooting Peonies
Although they are mostly free of insect pests, peonies may experience fungal diseases such as Botrytis and blight. Copper fungicide can be effective in treating diseases, and plants grown in full sun with good air circulation are less likely to have trouble.
Failure to bloom may be the result of planting too deep or possibly not enough sun. If your peonies have weak stems and floppy flowers that fall over, provide a peony cage or a “grow-through” support. If possible, harvest flowers for bouquets prior to rainstorms.
Favorite Peony Varieties
Popular Herbaceous Peonies
- ‘Karl Rosenfield’ (see above)
- ‘Sarah Bernhardt’: fragrant, double flowers in pastel pink
- ‘Felix Crousse’: double, crimson red flowers
- ‘Red Charm’: heavily ruffled, double flowers in rich red
Itoh (Intersectional) Peonies
- ‘Takara (Treasure)’: large, ruffled flowers open in light yellow with lavender-pink centers; fade over time to pale white with burgundy centers
- ‘Bartzella’ (see above)
- ‘Cora Louise’: semi-double, white flowers with lavender flares and a light scent
- ‘Keiko (Adored)’: semi double, bright pink flowers fading to soft pink
- ‘Canary Brilliants’: double salmon-pink and cream flowers fade to yellow