How To Grow Peonies
Peonies are always a favourite perennial in the garden. They are either herbaceous or woody, have attractive foliage, and most importantly, colourful, vibrant flowers that bloom in late spring to early summer. Many of these flowers are huge! Peonies come in over 30 species, but at the garden centre there are 4 commonly available ones:
Herbaceous Peonies (Garden Peony)
The most common species of Herbaceous Peony is Paeonia lactiflora. These plants emerge from the ground in spring, grow, flower, and die back to the ground in fall and winter. They re-emerge the following spring and repeat the cycle. They are long lived and can remain in place for decades. They are low maintenance, resist most pests and are somewhat drought tolerant and deer resistant. Some cold temperatures are required for them to flower reliably.
Fernleaf Peonies
Paeonia tenuifolia, also known as the Fernleaf Peony, is a collectors plant with green, fern-like, delicate foliage. Deep red or burgundy flowers bloom early, usually in Spring or early Summer. They are good reliable growers that may need to be staked as they grow larger. They are tough, mostly disease resistant but will benefit from cutting back foliage to ground level in the fall
Tree Peonies (Woody Peonies)
Tree Peonies, or Paeonia suffruticosa are woody shrubs native to Asia. Although they go dormant and drop their leaves, they also grow woody stems that stay above ground all year long. Some would consider them to be a small shrub instead of a perennial. Their most sought after feature is their huge flowers, some of which can reach up 10 inches across! Mature plants can be nearly 4-6ft across and up to 7ft tall.
Itoh / Intersectional Peonies
Itoh or Intersectional peonies are hybrids. Itoh Peonies get their name from Japanese breeder Dr Toichi Itoh. They are the result of genetic crosses of Herbaceous and Tree peonies. Large plants grow sturdy branches that don’t need a lot of support. Huge colourful and fragrant flowers appear later than herbaceous peonies. Usually in late spring and early summer. Colours vary but the most common are yellow, bronze, pink, red and white. They are mostly herbaceous. That is, they die back almost completely to the ground when dormant. With that said, they are hardier than most Tree Peonies.
Flower Types
Peony flowers are divided into six types:
- Single
- Japanese
- Anemone
- Semi-double
- Bombe
- Fully Double
Which Peony Has The Longest Lasting Flowers?
The Itoh or Intersectional Peonies have the longest lasting flowers. This is followed by the Tree Peony. The Herbaceous Peony flower lasts the shortest, usually 7-10 days per flower
How to Grow Peonies
Peonies need full to part sun but will benefit from a little bit of shade in the hottest part of the day. Soil should be moist, but well drained. Good air circulation is also important to reduce the likelihood of fungal diseases. One really important tip is to avoid planting too deep. Peonies that are buried too far underground may grow, but will be hesitant to flower. Make sure the “eye” or “growing node” is no more than 2 inches below the soil.
These plants also dislike being moved. Establish their location and avoid transplanting. Most herbaceous peonies grow really tall and grow large, heavy flowers. As a result, they will need to be grown with support like stakes or peony rings. Otherwise the weight of the flowers will snap the branches. Peonies are quite winter hardy. Many will survive all the way down to Zones 2-3
Watering Peonies
In general, Peonies are somewhat drought resistant, but will benefit from regular deep watering. Soil should be kept moist, but well drained for best results.
Fertilizing Peonies
The best time to feed peonies is in early spring just a new growth begins to emerge from the ground or from pre-existing branches. Use an all purpose or perennial plant fertilizer like our GardenPro Perennial and Vine food.
Peony Care
The most common issue with Peonies is that they did not flower. There are several main reasons for this. First, the plant may have been planted too deep. Growth nodes should be no more than 2 inches below the soil level. Second, the plant did not get enough food. Fertilizer with a Perennial or Flowering plant fertilizer in early Spring. Third, the plant did not get enough sunlight. Fourth, young peonies may not be ready to flower yet. Wait another a year or two, or buy larger peony plants to begin with.
Another common issue reported with Peonies is the presence of ants. Ants by themselves won’t harm the plant, but they could be an indicator that there are aphids present. A sharp spray of water or Insecticidal Soap should be all that is needed to manage an aphid outbreak
The third most prevalent issue is fungal disease. The symptom is blackened stems, buds or gray mold. Infected areas should be removed and destroyed. To reduce the chances of it happening in the first place, avoid watering the foliage and try to improve air circulation
Pruning Peonies
Peony pruning is dependant on the type. Herbaceous peonies will naturally die back to the ground. Simply remove spent foliage and clean up. Fernleaf peonies can be cut back to ground level in Fall. Tree Peonies don’t generally need pruning unless it is to shape, maintain size or remove dead, damaged or diseased wood. Itoh Peonies can be cut back to a few inches above ground when dormant, but don’t need to be. New buds will form along any older wood.