Tree peony for sale is best planted in the late fall before the first frost. Avoid planting in late spring and in summer. The hot and dry weather can hinder the plants' establishment. They are available in bare root, rooted balled tree, or container-grown grafted rootstock forms.
Depending on the size of the plant you buy, blooming can occur from the first year to 4 years after planting. Therefore, tree Peonies are not plants for the impatient gardener. Also, the flowers of a new plant may not reach their potential for several seasons.
Here are the growing requirements for a tree peony:
- Location – Place your tree peony in an open area where there will be good air circulation. However, avoid a completely exposed area without protection from strong winds. Also choose an area with partial sun for them to grow well. Tree peonies will tolerate light shade, but the plants may become straggly growing towards light. In addition, tree peonies can also be grown successfully for several years in a container about 30cm in diameter. When planting, it is important to use soil-based compost.
- Soil – Choose a soil that is fertile yet well drained which is neutral in pH to slightly alkaline. Dig a hole that is 12 inches wide and deep and incorporate some garden compost and bone meal or general fertilizer. Plant the bare root tree peonies deeply with the graft union at least 8 cm below the soil. This will encourage the plant to make fresh roots and basal shoots.
- Water – Do not overwater newly planted peonies. Tree Peonies are very drought tolerant once established. Avoid placing them near an automatic irrigation system. You would have to wait until the soil has dried down to 4 inches before watering deeply. Though established plants are drought tolerant, prolonged periods of drought may affect the flowering the following season.
- Feeding – Tree peonies are considered heavy feeders. They respond well to a generous amount of bone meal or rose fertilizer given in early fall. The high potash content encourages blooms to develop. You may also give a light sprinkling of a general fertilizer in spring.
- Mulching - In late winter or early spring apply about 4 inches layer of organic mulch such as leaf mould, garden compost or well-rotted manure to the main rooting area. Keep the base of the stems free from mulch.
- Pruning – The best time to prune your tree peonies is in early spring. Trim off all the dead wood just as the growth buds are swelling. Only remove dead wood in a young plant during the first 2 years to help get the plant established. After that, if it forms a good shape, no regular pruning is needed. There will be buds at the base of the stem or shoots coming from below the soil. Prune back to these or down to 15cm or less from the ground. Be diligent with deadheading spent blossoms and remove old flowers and petals from the garden.