The best companion plants for peonies

Anyone who has stood in front of a large peony bed in May or June is unlikely to forget the sight quickly. The lavish globes of flowers, their delicate fragrance and the rich green foliage can look almost unreal. It becomes especially interesting when the perennials are not simply planted anywhere, but paired deliberately with plants that support them visually and promote their health.

What peonies need before companion plants move in

Before deciding what will grow beside them, it is essential to understand what peonies themselves prefer. Peonies need plenty of light, or at least partial shade, along with deep, nutrient-rich yet freely draining soil. Winter waterlogging is harmful, as are overcrowded beds where no air can circulate around the leaves.

The reason is straightforward: when air remains still in a border and foliage does not dry quickly after rain, fungal diseases spread far more rapidly. Grey mould is particularly feared; this fungal disease turns buds brown and can spoil entire flowers.

• Position: full sun to partial shade, ideally exposed to airflow
• Soil: deep, humus-rich and well drained, without becoming waterlogged in winter
• Spacing: leave air around every perennial and avoid densely packed rows

When creating a new border, plant the peonies first, then arrange the other perennials around them. This keeps the emphasis in the right place: the flowering stars take centre stage, while their companions work in the background.

The best companion plants for peonies: perennials that enhance the floral display

Lady's mantle as a soft carpet

Lady's mantle is a classic choice for a perennial border. This plant forms dense, rounded mounds of soft, circular leaves. In early summer, it is covered by a haze of tiny yellowish-green flowers. That contrast makes the rounded peony blooms appear to leap forwards visually.

"The gentle veil of lady's mantle flowers makes the bold peony colours look as though they were photographed in a professional studio."

It is practical too: lady's mantle stays relatively low, barely intrudes on peony roots and shades the soil without covering the perennials themselves. The pairing works just as well in a vase as it does in the border.

Bellflowers and other perennials with nodding blooms

Bellflowers and similar perennials with drooping, bell-shaped flowers bring a sense of lightness to the planting. While peonies dominate with their large, rounded flower heads, bellflowers add numerous smaller bursts of colour between them.

Choosing the right variety matters: tall, spreading types are better placed at the back of the border, whereas compact varieties can grow close to the peonies. They compete little for nutrients and light, while noticeably extending the overall flowering period.

Hydrangeas as a calm backdrop

Where there is sufficient room, hydrangeas can be planted behind peonies. These shrubs also produce weighty flower heads, but in the background they create a calm wall that makes the perennials stand out even more. Given enough space, hydrangeas provide light shade during the hottest summer weeks without leaving peonies permanently in darkness.

As hydrangeas generally get going a little later, they create a natural handover: peonies dominate first, before the shrubs gradually take over the display.

Plan a flowering succession with iris, alliums and daylilies

A thoughtfully designed border ensures that something remains in flower from spring well into summer. Peonies may be magnificent, but their main season is limited. Other perennials and bulbs can fill the gaps.

• Iris: usually flower shortly before peonies, have similar requirements and create strong colour effects.
• Ornamental alliums (Allium): rounded flower heads, vertical accents and ideal for planting among perennials.
• Daylilies: often begin as peonies start to fade and continue into high summer.

With their upright leaves, irises give the space structure, whereas peonies tend to form broad, bushy clumps. Alliums add vertical markers with tall stems and purple globes, creating striking sightlines alongside peony flowers. Daylilies take over in high summer, preventing the border from looking empty after the peony season.

Lavender as a fragrant bodyguard for peonies

Lavender is an almost ideal partner. It likes warmth, sunshine and free-draining soil, just like peonies. Planted along the edges or in front of the perennials, lavender forms an aromatic line that does more than look attractive.

"Lavender protects the peony bed with its scent like an invisible fence against uninvited guests."

Many insects and animals that nibble leaves and flowers avoid its intense scent. These include mosquitoes, flies, some pest insects and, in rural areas, even deer. Ornamental alliums reinforce this effect: their slightly sulphurous scent deters a number of insects without bothering the gardener.

Using protective planting effectively

If bellflowers or other more vulnerable perennials are included in the border, frame them with such scented plants. This reduces the risk of pests multiplying in large numbers and eventually affecting the peonies too.

Plant	Main benefit alongside peonies
Lady's mantle	visual enhancement, ground cover, soft transitions
Bellflowers	delicate addition, longer flowering season in the border
Hydrangeas	backdrop, light summer shade
Ornamental alliums	vertical accents, light protection from pests
Lavender	scented barrier, insect deterrent, structure at the border edge

These combinations harm peonies over time

Although peonies look robust, some neighbours make life difficult for them. Vigorous root competitors and species that prefer permanently wet soil are problematic. Neither suits the nature of these early-flowering perennials.

Large, spreading ornamental grasses or very expansive perennials with strong rhizomes deprive peonies of light and nutrients. Within a few years, only a handful of weak shoots may remain. Plants that require constant moisture also create a microclimate in which fungi can thrive.

"Anyone who loves peonies avoids close planting with spreading grasses and permanently damp companions."

The rule of thumb is this: anything that grows so densely that the soil beneath is barely visible should not be planted immediately beside peonies. An open border with clear spacing and carefully selected companions is the better approach.

Practical tips: planting distances and care techniques

A common mistake is filling a border completely from the outset. Peonies need several years to reach their full size. Those given sufficient space will later reward the gardener with ever larger towers of blooms.

• Plant peonies at least 60–80 centimetres apart.
• Position low-growing partners, such as lavender and lady's mantle, at the edge, with taller plants behind.
• Remove wilted leaves after heavy rain to give fungi fewer opportunities to take hold.

Once established, peonies prefer to be left undisturbed. Repeated division or transplanting often delays flowering for years. It is better to introduce new companion plants carefully into existing gaps rather than digging around the peonies themselves.

Why companion planting makes such a difference for peonies

Peonies can look good on their own in a lawn, but their potential is far more apparent in a mixed perennial border. Colourful companion plants, varied growing heights and the right fragrant backdrop can turn a few perennials into a true focal point that neighbours stop to admire every year.

For amateur gardeners, it is worthwhile playing consciously with contrasts: delicate clouds of flowers against large blooms, upright allium stems against rounded peony clumps, and the cool violet tones of lavender against the warm pink and cream shades of the perennials. A little experimentation quickly reveals why professionals refer to "companion plants" rather than mere filler.

The resilience aspect is equally compelling: scented barriers, airy planting distances and suitable soil companions noticeably reduce disease pressure. Instead of relying on fungicides, gardeners use plants that reinforce one another. The result is a border that not only looks spectacular in May, but also flowers reliably for years - and that is precisely the special appeal of well-combined peonies.