Don Hollingsworth is an American hybridizer who introduced many fine varieties and is well-known within the peony community for giving plenty of advice, both in publications, newsgroups and personal e-mail correspondence. He used to run a very good peony nursery, aptly named hollingsworthpeonies.com, where many difficult to find varieties were available. This is one of his many, many articles he has written over the years.
Growing fine peonies almost anywhere.(1)
Peonies are among the elite of ornamentals. When well provided for they give increasing rewards for years and will continue to do so indefinitely. Peonies which were planted long ago are often seen flowering around older homes. They are sometimes seen at abandoned house sites where they continue to flower regularly. When suitably positioned, peonies planted today will give similar results.
In order to perform well peonies must grow well and attain mature size. New plants may require two or more seasons to reach the state of growth necessary for them to give typical flowering, depending upon the growing conditions they are given, and upon the natural habit of the individual variety. While they will tolerate poorer soils, provided their other needs are met, it may take several seasons to see a flower.
What it means for a peony to grow well is that during each growing season the plant stores as much food as possible, producing big storage roots. This enables the annual increase of stems and flowers until the plant reaches an equilibrium with its environment. While the same things can be said of many garden perennials, what is special about peonies is that they produce relatively very large plants during a short period of rapid growth. As with spring bulbs, this growth comes mostly from stored food.
Peonies grow best in a fertile, well‐aerated and well‐drained soil, such as will grow a good vegetable garden. Since they are long‐lived perennials any modification of the soil in their root zone must be done before they are planted. That is where the idea of a “hundred dollar hole” for a “ten dollar plant” gets its merit. A most prevalent problem around many new residential developments is low humus levels of the soil. Any substantial correction will have to be made as part of the initial site development.
Although peonies may tolerate low fertility, they develop accordingly slower in poor soils. Peonies growing under such conditions will benefit from periodic top‐dressing, possibly needing sources of both the major nutrients and the minor nutrients (trace elements). Depending upon the availability of suitable materials, either organic sources and/or more refined products may be used.
Peonies also tolerate dryness, but don’t expect them to be producing and storing food while the soil is dry. Further, prolonged moisture stress can be expected to bring on early die‐off of the foliage and the end of development for the season. If this does not occur until the last half of summer, the effect on long term performance may be minimal, but the foliage deterioration will be unsightly for the remainder of the season. In chronic moisture‐stress climates, sites protected from direct sunlight during the “heat” of the day and sheltered from hot, dry winds will offset some of the adverse effects of low soil moisture, while judicious irrigation can give the plants the moisture they need to function. Avoid watering around the base of stems. Especially when using high volume water delivery, it is best applied around the circumference of the leaf canopy, as in a shallow moat meant to moisten the outer half of the root zone.
Peonies may benefit from treatment for leaf and stem diseases, which become more pressing under conditions of prolonged high humidity. While the plants are generally tolerant of partial leaf loss to summer leaf diseases, early spring infestations as occur during cool, humid periods may be more devastating, sometimes leading to stem death and crown rot. Under such conditions, the plants may benefit from a timely application of suitable fungicides. However, the first level of disease management is prevention. Select sites having good air circulation, especially during early spring. Sanitization is next—clean up and dispose of old foliage and dead stems in the autumn to reduce carry‐over from one season to the next.
Peonies will not tolerate poor aeration of the root zone. In order for the plant to extract what it requires from the soil it expends energy, which is released through respiration, requiring oxygen. Any time the soil pores (the voids between the soil particles) are loaded with water, the air is excluded. Peony roots may reach 18 inches deep, or more, depending on habit of the individual variety. There needs to be someplace below the root level to where excess water can percolate away. For good plant health the excess needs to drain away within hours after cessation of rain or irrigation.
For an unknown site, you can determine the drainage characteristics by a percolation test, as might be used to evaluate a site for a septic tank absorption field. Dig a hole 18 inches deep, fill it with water enough times that the surrounding soil is well wetted. Then refill it and time how long it takes for the water to get away. An hour or less suggests an excessively droughty site. Three to six or ten hours may work very well with an ordinary calendar of rainfall. However, if water remains in the hole after 24 hours, you have a chronic wet‐land. Either install mechanical drainage measures to change the situation or select another site for your peonies. Raised bed strategies may also be of help, depending upon site and design.
Remember, naturally excess water is often seasonal. A site which may look just fine in the relative dryness of autumn may be wet next spring when the plants are making their most important growth. That is where the percolation test comes in.
Some peonies are more sensitive to poor aeration of the soil than others. The so‐called tree peonies (actually shrubs) and many of the natural species are (or act) as alpine plants and may do best in a coarse soil having good drainage, provided they are adequately protected from moisture stress, as discussed earlier, which will be especially important in hot locations. Shade and shielding from hot summer winds may enable better performance, particularly in the midwest United States.
- Hollingsworth, Don. “Growing fine peonies almost anywhere.” In: Paeonia, 1994, vol 24, no. 1, pp. 5-6.