Lafayette County Master Gardeners: “Herbaceous Peonies”

The Lafayette County Master Gardeners are once again hosting their Spring Lecture Series at the Lafayette County & Oxford Public Library located at 401 Bramlett Boulevard. The lectures will be held at noon in the auditorium of the library. They are free and open to the public. The dates are Thursdays March 7, April 4, and May 2. Make sure you add these dates to your calendar.

The March speaker is Dr. Christopher Cooper, County Director and Master Gardener Coordinator with the UT-TSU Shelby County Extension Service. The title of his presentation is “Nine Sustainability Principles.” These nine principles will assist residents and neighborhood associations with practices they can apply in their yards and common spaces to create healthier living spaces and communities. The aim of the presentation is to help homeowners achieve a landscape that reflects their values, desires, and needs while ensuring the protection of invaluable waterways.

A native of Jackson, Mississippi, Dr. Cooper is the UT Extension County Director and Coordinator for the Extension Master Gardener Program in Shelby County. He can be found throughout Shelby County conducting educational programs addressing issues that affect urban and home horticulture. For any questions, contact us at lcmga38@gmail.com.

This is the first in a series on Peonies (genus Paeoniaceae). We will cover the three types of peonies: herbaceous, tree, and Itoh (also called intersectional). Herbaceous peonies (P. lactiflora) are the most common and feature bushy mounds that die back to the ground in winter. Tree peonies (P. suffruticosa & more) are upright, multi-stemmed and woody and the woody stems are maintained year-round for next year’s growth. Itoh/intersectional peonies are a hybrid of the herbaceous and tree peony and have short woody stems that die back to the ground in winter. This article will focus on herbaceous peonies.

Peony plants are perfect examples of the growing adage “sleep, creep, then leap.” While they take three years to begin fully flowering, they have a life expectancy of one hundred years! Their large, fragrant blossoms are a mainstay of spring. They are native only in the Northern hemisphere, throughout much of Europe and Asia. For those looking for native American plants, Brown’s peony (Paeonia brownii) is native to the northwestern United States. The woodland peonies (P. japonica and P. obovata) and are best suited for shade gardens. Peony flowering occurs for seven to eight weeks, from the end of April until early June (hardiness zones 6 to 7). Flowers typically bloom in this order: woodland peonies, followed by tree peonies, and then herbaceous species, and ending with intersectional hybrids (Itoh). Designing a garden with a continuous eight weeks of flowers is a challenge that produces amazing results.

Peonies are hardy in zones three through eight, but there are some varieties more tolerant for southern climates.

Festiva Maxima has red-flecked white blossoms that grow up to 3 feet tall. Blooming in June, this deer-resistant and fragrant peony is a durable variety. This plant is beautiful even after flowering is finished for the season, as it features glossy, deep green foliage.
Coral Charm is an early-blooming selection producing notably large flowers. This selection is a stand-out with large, semi-double, incurved petals in a unique coral-peach color that fades to pale ivory. Select this peony during full bud for an excellent cut flower lasting over a week.
Kansas is a long-blooming, reliable selection that thrives in full sun. This peony blooms heavily in late spring or early summer, making it an early midseason variety that flowers for about seven to 10 days. This variety is attractive to butterflies but deer and rabbit resistant.
Sarah Bernhardt named for a legendary stage actress, features perfumed pink blossoms, silvery edges, and layers of ruffled petals. It is a reliable and vigorous blooming flower that retains attractive foliage until the first frost. This peony is ideal for bordering a walk or driveway.
Nippon Beauty is a prolific bloomer that produces an abundance of deep red blooms. Enjoy this plant’s foliage until the first frost as it retains a dark green, glossy appearance. Grow this peony in an area protected from harsh winds and heavy rains.

The best time to plant peonies is in the fall. Why am I writing an article about peonies now? Well, check out gardening supply stores and big box stores and they are selling peony tubers now. Fall is ideal, but feel free to pick up some varieties and plant them now. Be sure to sow the plant in the appropriate location: herbaceous peonies prefer full sun (to part sun), leaving three feet between plants for air circulation and allowing for the expected three feet wide by two to three feet height of the mature plant. The plant requires well drained soil, standing water can cause root rot and kill the plant. Peonies prefer neutral to alkaline soil. Herbaceous peonies have fleshy, thick tuberous main roots with a head-like crown and secondary thin fibrous roots. Sitting on top of the crown are white or pink-colored shoot buds or eyes. Herbaceous peonies are planted bare root with attached crown and buds (at least three to five). Plant so the pink buds at the top of the root are one to two inches below the soil level. Planting too deeply will reduce or prevent flowering. Ants are commonly seen on peony blooms. Ants are attracted to the sweet nectar produced in peony buds. The insects won’t harm the plant and are not required for the peony to properly bloom.

When maintaining your peonies, it is necessary to support the large showy flowers by staking individual flowering stalks with supports and twine or by using a peony ring especially designed for this purpose. Once flowers are spent, remove the dead flower heads. In many instances, you can remove the stakes or peony ring to be used on other droopy flowers. Lightly mulch peonies with shredded wood mulch keeping the mulch two to three inches from the base of the plant. When watering is required, focus water on the ground and avoid wetting the leaves. Avoid fertilization with high nitrogen as this will produce lots of leaves and reduce flowering. Herbaceous peonies die back to the ground during winter months. When this occurs, you need to cut spent stalks as they are quite tenacious and won’t necessarily pull out of the ground when the plant withers and dies. Remove the peony foliage from the garden and destroy it. The removal and destruction of the peony debris helps to control leaf blotch and other fungal diseases.

It’s not necessary to divide frequently; plants will continue to flourish for more than thirty years without requiring dividing. You can divide more frequently to propagate additional plants. In fall, to divide a mature herbaceous peony, carefully dig up the plant, wash off the soil, and remove any rotted material. Locate the pink to white-colored buds or eyes at the top of the crown. Using a clean, sharp knife, divide the crown into wedges, ensuring that each wedge has at least three to five buds and one to two large roots to nourish and support the plant.

Peonies are susceptible to powdery mildew, a dusty looking coating on the leaves. This will not harm the plant but is unsightly. Peony leaf blotch is another fungal disease which causes large, brown spots. Peony leaf blotch is caused by the fungus Cladosporium paeoniae. Fungal diseases can be controlled through sanitation—removing fall debris and destroying the foliage. Adequate spacing also provides aeration to prevent fungal disease. When watering, water at soil level and minimize wetting the leaves.

The browning of the peony buds in spring is likely due to botrytis blight. Botrytis blight is a common fungal disease of peonies. The fungus Botrytis paeoniae attacks stems, leaves, and flower buds. It is most common in cool, rainy weather. Young shoots attacked by botrytis blight discolor at the base, wilt, and fall over. Affected flower buds turn brown and fail to open. The withered buds are later covered with a mass of gray, fuzzy fungal spores. Infected leaves develop large, irregularly shaped dark brown spots. Botrytis fungi survive in debris left in the garden over winter. In spring, remove withered flower buds and spent flowers. In fall, cut off the peony stalks at ground level. Remove the plant debris from the garden and destroy it. If the peonies are growing in partial shade, move the plants to a sunnier location.

If peonies are your passion, consider attending the 2024 American Peony Society Convention in Bloomington, Minnesota, on June 5–9, 2024. For more information, see the American Peony Society Webpage of select here.