Tree Peonies are ideal for Australia’s harsh dry conditions and current water restrictions. Their growth pattern is very similar to bulbs from early autumn through winter. The root system is activated by cold and feeding roots are active. This is the best time to add N.P.K. In spring they shoot and flower, then shut down for summer when no water is required.
- Once the right amount of lime is applied they will tolerate a wider range of soil conditions. Once established they become drought tolerant.
- Initially they are expensive, due to difficulty of propagation and grafting of Japanese varieties, which do not do well on their own roots. They are slow growing and from division can take 3 years to commence flowering.
- They can suit any small garden, growing 1m x 1m in 10-15 years.
- There is a wide range of colours from black-red through to dark yellow – almost every colour represented except for blue. Also many blended-suffused from single to semi-double and full double flower forms. Some European types are over-doubled and hang down. These can be picked and floated in a shallow bowl Japanese style (kinshe and flambeau are good examples).
- Good dissected foliage on Lutea hybrids suit cottage gardens and perennial borders, they blend well with other low growing plants. Chinese Dragon and Black Panther are good examples.
- There is a current influx of Chinese varieties. These are proving to be very difficult to grow. Recent trialling which involves adding 30-40% more lime has been shown to give more promising results.
- As modern gardens become smaller and smaller, these exotic shrubs will become even more suitable given their slow growth and ultimate size.
- Water is a limited resource and costly these days. Once a tree peony is established (1 to 2 years) watering in summer is not required. Even in long hot dry periods their root system is shut down and only re-activated early autumn when feeding commences.
- When people talk about peonies they usually relate to the herbaceous type which grows flowers and then dies down to ground level every year. These are divided every 3-4 years and can be grown cheaply. Tree peonies are slower growing and are hard to build up plants rapidly. Young divisions are not hardy and must be grown in containers for at least 2 more years before they are saleable. Your average tree peony in a 10inch pot is a 5-year-old plant; this explains why they are so expensive.
- Tree Peonies can be spring planted, but be prepared to water the plant in any dry period, say 10-14 days giving it a good soak is much better than short frequent doses. A sign of dry stress will be drooping foliage. If the leaves are browning and crisp on the edges means you are not watering enough.
WHAT TO EXPECT FROM YOUR TREE PEONIES
Patience is required to grow these plants. First flowers may not be true to size and colour. Do not be disappointed; allow one or two season to develop. Once they start to bloom the exotic flower is so rewarding. Tree peonies grow for many years and if cared for will bloom annually. Careful consideration should be given in selecting the location for planting the Tree Peony. Partial or high filtered shade will lengthen the life of the blossom. They should be sheltered from strong winds.
PLANTING: Tree Peonies must not be spring planted unless well potted. Plant in autumn/winter/spring from containers. Select a well-drained place with at least half a day of sunlight. The bloom will last longer if sunlight is filtered during the heat of the day therefore morning sun is preferred. Tree Peonies prefer a high pH 6.5 to 7.0 – most average soils will have a pH of 5.0 to 5.5. In the planting hole that should be 50cm deep, the equivalent of a 250cm pot of dolomite lime must be incorporated, as the Peony must have high calcium magnesium content to grow successfully. Dolomite is a very good soil conditioner. This amount of lime may seem excessive but it has been proven to grow the strongest tree peonies. After 2 to 3 years of growth, if the plant is lacking in vigour and not flowering, more lime can be applied in a good layer around the plant. Carefully break the surface with a fork. Two to three year old divisions planted in autumn from 8inch to 10inch pots should flower the following spring. Surface organic mulch is recommended to moderate soil temperature fluctuations in summer only. Do not crowd the centre of the bush, just around the plant. Tree Peonies, unlike all other plants, do all their root feeding and storage in the coldest months of the year from mid autumn, before leaf fall, to the end of winter, when pink roots appear. Once the ground has been prepared with organic life and copious amounts of lime, they can be fed N.P.K. chemical fertilizer, preferably low in N but high in P and K. Also give Iron in the form of Ferrous Sulphate, which is readily available. A small handful of each, spread around the base of the plant once a month for the four coldest months is sufficient. If the plant is 3-5 years older, more can be applied.
FLOWERING: The first could be pinched out, as they are often small in size and not true to colour. The following spring leave them to flower.
CULTURE: In autumn when the leaves begin to fall, it is advisable to remove them and any other debris, being careful not to damage the plant in any way. Leaves left on the ground could have disease spores that might survive winter and cause infection in spring. Whenever the weather is dry, supplementary watering is beneficial. This is especially true while they are in bloom. If mulched in summer, water only in extremely dry conditions because there growth underground is mainly autumn-winter. They can be very hardy to dry conditions, as their root system is basically not active.
POT CULTURE: If you have very limited space and only have a very small garden or patio etc. they can be grown very successfully in pots. The basic requirements are excellent drainage in the form of good quality potting mix and the addition of 2-3 handfuls of Dolomite each time when re-potting.
DRAINAGE: Good drainage is absolutely essential. Tree Peonies will thrive in most garden soils. If sandy, dig in peat moss and well-rotted (not fresh) animal manure and after planting leave a well. In clay or very heavy soils, mound up at least 15-30cm, do not dig down. If the required amount of lime is added, the clay will break up readily. If it is sticky, a liberal amount of gypsum will also help.
PRUNING: Usually it is only necessary to remove dead or broken branches. They should be removed when the growing season starts so as to make sure there is no life in these branches. In areas where Tree Peonies are prolific in growth, the centre of the plant should be kept as open as possible to allow sunshine and air to circulate.
CHLOROSIS: Due to the addition of lime to increase pH in some soils, the Tree Peonies may take on a chlorotic appearance – the foliage is a yellowish colour and the leaf veins are prominent. This is easily corrected. A month before growth commences in spring, and once more after, sprinkle a good handful of Ferrous Sulphate or water in some iron chelate.
AFTERCARE: After initial planting, Dolomite lime can be applied around the plant every 3 years. Be generous – 3-4 double handfuls or a 1 inch layer is fine. A good indicator of not enough lime is shoots dying back over the winter and tip buds, brown and rotted. The plant will survive this and shoot out lower down.
TESTING YOUR SOIL: To make sure your garden soil is correct to grow tree peonies use any pH kit with a colour chart liquid dye and white powder. Get a cube of soil 3cm x 3cm, drip 5-6 drops of liquid and puff with the powder; any yellow colouring will indicate acidity. This means not enough lime is present, so add more. Dark colouring means 6.5-7.0 pH – the correct range of pH for tree peonies
Information courtesy of:
Lot 2 McAllister Road,
Monbulk. Vic.
(03) 9756 7557