Caring For Tree Peonies
Get the Best From Your Tree Peony
- Plant in part or full shade
- Good rich soil
- Trim off dead wood each spring
- Stake when in flower if necessary
- Feed in both spring and autumn with bone meal
Where to Plant a Tree Peony
Tree peonies are extremely hardy and thrive best in part sun, part shade, or even full shade. They prefer an open situation as air movement around the plant helps keep it healthy. However, avoid a completely exposed position where flower petals could blow away quickly. Tree peonies prefer a fertile yet reasonably well drained soil, which is neutral to slightly alkaline. Clay, chalk or sand are all fine, as long as they do not become too wet in the winter.
Planting a Tree Peony
Bare root or root balled tree peonies will be sent when dormant, from October. If you are unable to plant for a few days, keep them in a cool dark place. Containerised and container grown plants are supplied throughout the year, and can be planted at any time that the soil is workable, although planting in the autumn is always preferable.
Dig a planting hole 30cm(12in) wide and deep, incorporating some garden compost and a handful of bone meal or general fertiliser. Plant bare root tree peonies deeply, most are grafted, and so the graft union should be at least 8cm below the soil. This will encourage the tree peony to make fresh roots and basal shoots.
Pot grown, rootballed or containerised specimens of all types should be planted slightly deeper than the current soil level. Water well after planting, and during the following summer.
Usually a tree peony will grow away in the spring, producing large handsome leaves and often some new shoots from the base. However, the main stem may not produce a shoot from the tip and may even die back. Depending on the size of the plant you buy, flowering can happen any time from the first year to 4 years from planting. Sometimes a plant will appear to make little growth, if any, in its first season. However, providing the foliage looks reasonably healthy, don’t panic. This may just be a settling in period. Occasionally the main stem may die back a little. Although this might be worrying, wait until the next spring when vigorous growth should resume from the lower part of the stem or even from below soil level.
Look out for suckers from the herbaceous rootstock and cut these off at ground level if they appear. The foliage is quite different from that of the tree peony.
Feeding a Tree Peony
Tree peonies are heavy feeders and respond well to a generous, early autumn top dressing of bone meal or a rose fertiliser. The high potash content encourages flowers to develop. A light sprinkling of a general fertiliser can be applied in spring.
Pruning & Trimming a Tree Peony
Tree peonies respond well to pruning. You should aim for a broad, multistemmed shrub of up to 120-150 cm in height, which will not need staking. In February, just as the growth buds are swelling, trim off all the dead wood. You will often find that the new shoots are coming from lower down the stem, leaving a small dead spur. Whole branches will sometimes die. These should be pruned back to a live bud or to just above ground level.
You can watch our tree peony pruning guide video below to see how it's done:
With a young plant, only remove dead wood during the first 2 years to help get the plant established. After this, if your plant forms a good shape, no regular pruning is needed. However, if your plant has few stems and is poorly shaped, then prune hard. You may see 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. Even if you can’t see any basal buds, adventitious ones will form. The best time to prune is early spring, although this may mean you sacrifice some flowers in the coming year. You can also prune directly after flowering but regrowth is slower.
If you have or inherit an old tree peony, which has never been pruned, it can be transformed and rejuvenated by applying the following technique. Prune just one or two main stems each year, cutting it down to about 15cm. It takes courage, but is usually successful. If the plant has just a single stem, prune it back in early spring.
Moving a Tree Peony
There are no problems about moving even a large, mature tree peony. Just move it during early autumn as you would any other woody deciduous shrub.
Tree Peonies in Pots
Tree peonies can be grown successfully for several years in a container about 30cm in diameter. When planting, it is important to use a soil-based compost such as John Innes No.3. Do not overwater.
Tree peonies rarely suffer problems from pests and are unpalatable to rabbits and deer. The only disease you are likely to encounter is peony wilt (Botrytis). This may appear in early spring, usually before flowering. Good hygiene and cultural practices is the key to preventing and dealing with fungal attack. Maintain a good airflow around the tree peonies by not overcrowding them with other plants, particularly at ground level.
If any stems collapse with Botrytis, or if any leaves become spotty, remove them immediately this will help prevent the spread of infection. Fungal spores of peony wilt over winter on old foliage, it is important to pick up and burn old leaves in the autumn.