Gardening Articles: Flowers :: Perennials
Chinese Tree Peonies (page 2 of 3)
by Kasha and David Furman
Where and When to Plant
In China, tree peonies grow from the edge of the Gobi Desert to the very warm areas south of the Yangtze River. Translated to USDA Hardiness Zones, that means the plants are hardy from zone 4 (southern Minnesota) through zone 9 (parts of southern California). Our experience tells us that the plants need a three-week dormancy period in the fall, with temperatures of 35 to 40°F.
Planting success has two key elements: plant at the right time -- fall -- and start with plants that are old enough and strong enough to survive transplanting. We suggest you buy from growers who sell only plants that are at least three years old. These will cost more, but younger plants, even though less expensive initially, more often fail to survive transplanting.
Buy from a reputable nursery that ships plants in fall, and plant as soon as the dormant bare-root plants arrive, a moment that will vary according to where you live. Plant in September if you live in zone 4, November in zone 9.
Don't plant too early, or plants will produce leaves that die as soon as cold weather arrives. Plant too late (after soil temperature is below 40°F), and the plant won't have time to produce the root hairs it needs to support growth in spring. Avoid planting in spring, when plants will put out top growth at the expense of developing a good root system.
Planting and Care
Choose a location that receives no more than four hours of direct sunlight with afternoon shade, or day-long dappled shade. Soil should be moist, fertile, and humus-rich; amend it if necessary. The plants will grow rapidly in full sun; however, under those conditions the flowers will go through their life cycle in just a day or two. Planted in semishade, flowers last 10 to 14 days (the bloom cycle lasts about 31/2 weeks).
In China, tree peonies will grow in acidic soil with a pH of 5.8. They also do well in Tasmania, Australia, where the soil pH is a slightly alkaline 7.5. However, experience tells us that tree peonies thrive best in soils with a pH of 6.5 to 7.0.
In a ninth-century gardening text, Chinese growers advised siting the plants where water drains quickly. This instruction means that tree peonies must be planted in a raised bed, on a slope, or in a garden bed that has excellent drainage.
To save time, dig planting holes before plants arrive. Make holes 2 feet deep, 2 feet wide, and no closer together than 5 feet. Set the plants deep enough that all pink or white buds at the base are at least 2 inches below the surface. Spread the roots, backfill about one-third, and "mud in" the plants with a mix of water and commercial seaweed with fish fertilizer. Make sure all air spaces are filled. Add the rest of the soil and mud in again. Fertilize with seaweed or fish fertilizer every three to four weeks after spring flowering has finished.
In warmer climates, force dormancy in November by trimming off green leaves and withholding water in November and December. New leaves will appear in January, with blooms in February and March.