Blooming of peonies: summer’s most anticipated event—your guide to peony plant care, fertilization and growing

The peony is one of the most cherished and beloved perennials in Finland. For instance, Paeonia x festiva has been grown in Europe since the 16th century, and it became popular in Finland as an ornamental plant in the 19th century. The pink ‘Rosea Plena’ and the red ‘Rubra Plena’ represent some of the old varieties of this classic peony. Paeonia x festiva grows widely across Finland, often blooming as early as June.

The Chinese peony (Paeonia lactiflora) is traditionally known in Finnish as ‘noble peony’. Today, there are hundreds of varieties available, including such common varieties as ‘Sarah Bernhardt’, ‘Festiva Maxima’, and ‘Bowl of Beauty’. Chinese peonies typically start blooming in late June.

Additionally, there are species peonies that can grow in the wild, such as Paeonia anomala, Paeonia obovata (woodland peony), Paeonia veitchii, and Paeonia tenuifolia (fernleaf peony). However, most fernleaf peonies grown in Finland are actually hybrid peonies (Paeonia x hybrida), a hybrid of the fernleaf peony and Paeonia anomala. Most species peonies are the earliest of all bloomers, starting in late May.

Peony plant care—tips for thriving plants

Ideal peony planting locations

Peonies flourish in sunny spots. Their blooms last longer when they can enjoy light shade during the midday heat.

Chinese peonies, the Paeonia anomala variety and hybrid peonies prefer the typical garden soil: loose, nutrient-rich, limed soil. Fernleaf peonies, on the other hand, thrive in deep, sandy, rocky areas that allow water to drain away from the base of the plant.

Drain the planting site well, as standing water can rot the roots. Clear the area of perennial weeds before planting to give your peonies a strong start. Peonies appreciate being left to grow in peace at first, and they typically bloom a few years after planting, relocating, or dividing.

In the case of clay soil, it is definitely worth it to build a raised bed with proper drainage to prevent moisture from accumulating around the roots. You can also construct the peony bed entirely above ground [in Finnish].

You can plant various types of peonies in the same bed about half a meter apart. They can also be planted individually among other perennials, provided the planting hole is sufficiently large and the peony doesn’t have to compete with more vigorous species.

Peony care

Weed the peony’s growing area each spring, taking care not to damage the roots. Sand mulch, for example, can make weeding easier, but ensure that the growth buds of the rhizomes are not buried too deeply under the mulch.

In autumn, check that a couple of centimeters of soil or sand cover the rhizome.

Wilted flowers typically drop their petals, so cutting off flower bases is optional. However, it can be beneficial. Occasionally, double-flowered peonies’ blooms wilt in place and can be neatly trimmed off. Cut off wilted stems in fall or spring.

Peony fertilization

If you fertilize the growing medium of your peonies during planting, you won’t need to fertilize your peonies for a few years.

For fertilizing in spring, nitrogen-rich, multi-nutrient fertilizers or well-rotted manure or compost are suitable for peonies. Spread fertilizer away from the peony’s shoots and buds, ideally about half a meter from the stems.

You can also give your peonies autumn fertilizer in early August.

Peony soil liming

Peonies thrive in soil with a pH of 6–7, though requirements vary by species. For instance, the Paeonia anomala variety tolerates more acidic conditions.

Watering your peonies

Once taken root, peonies generally don’t need watering, as their roots grow deep. The critical watering periods are during in May–June, when peonies develop their flower buds, and in August when next year’s buds form. In dry conditions, water your peonies two to three times in spring and again in August.

Supporting your peonies

Double-flowered peonies have heavy blooms, particularly after rain, so they benefit from support. There are various support frames available, although metal supports are the most durable. You can also craft your own supports from rebar, for example. The simplest method is to place a metal support around the rhizome at planting or, at the latest, by early June. This support can remain in place year-round.

Transplanting peonies

Peonies prefer not to be moved and appreciate stability. However, if necessary, even large plants can be transplanted. You don’t need to divide the plant when moving it, but if your peonies are old and blooming less, dividing may help. If you devide a peony during transplanting, do so in August–September.

Simply changing the location can be done in early spring when new shoots emerge. The root system of a mature peony is extensive, requiring significant effort to dig. Replant the peony at the same depth as it was before. After transplanting, you can expect a “demonstration” from the peony, that is, a few years of reduced blooming, especially if it was divided.

Propagating peonies

Peony hybrids and Chinese peony varieties can be propagated by division. Divide peonies preferably in early autumn.

Paeonia anomala and other non-hybrid species can be grown from seeds. The seeds need both a warm and a cold treatment, called stratification, to germinate. So, it is ideal to sow them in late spring as they ripen. This timing allows the seeds to get the necessary warm treatment in summer and cold treatment in the following winter. During summer, the seeds develop a radicle, and in the following spring, they produce seed leaves and eventually true leaves.

It is possible that not all the seeds germinate in the first spring, as some may sprout after up to four winters. Sometimes the seed sowing can also fail: if the seeds dry out too much, the radicles can die.

You can also simply let the seeds fall to the ground naturally. With luck, new seedlings may appear at the parent plant’s base, and you can then move them to location you want.