Peonies: the best companion plants for a spectacular border

Many amateur gardeners plant peonies on their own in a border, then wonder why the dramatic wow factor never quite appears. Although these perennials are impressive in their own right, they only reveal their full potential with suitable companion plants – and enough breathing room around every specimen. Follow a few basic principles and you can create a border that looks like a painted picture from spring through to high summer.

What peonies really need before their neighbours move in

Peonies are among the longest-lived perennials in the garden. They often remain in the same position for decades without needing to be moved. That is precisely why it pays to plan both their location and their planting partners with care.

“Peonies love sunshine, deep, nutrient-rich soil and, above all, space from pushy neighbours.”

Here is an overview of their most important growing requirements:

• Light: Full sun to light partial shade; ideally, they should receive at least 5–6 hours of direct sunshine daily.
• Soil: Deep, humus-rich and free-draining, without remaining waterlogged through winter.
• Root competition: Avoid planting vigorous shallow-rooted plants or woody shrubs immediately beside them.
• Spacing: Each perennial needs a clear area around it, allowing foliage to dry quickly after rain.

An overcrowded border retains moisture for too long. Fungal diseases such as grey mould can spread, ruining entire flushes of flowers. An open planting scheme is therefore not merely an aesthetic choice; it is a form of plant protection.

Lady’s mantle and bellflowers: a gentle stage for large blooms

Once the basics are in place, attention can turn to the design. Certain perennials make peonies appear even more lavish without competing for attention.

Lady’s mantle as a soft carpet

Lady’s mantle (Alchemilla mollis) is a classic peony companion. It produces dense yet low cushions of pleated leaves, topped in early summer by a haze of yellow-green flowers.

This pairing offers several benefits:

• The delicate clouds of flowers enhance the soft pink and cream shades of peonies.
• It stays low, so it does not crowd the peonies.
• When cut, it makes an excellent filler for peony bouquets.

Bellflowers for playful contrast

Compact-growing bellflower species complement peonies particularly well. Their nodding or upright bell-shaped flowers add lightness to the border. They usually flower slightly later, extending the period during which the planting looks attractive.

Spacing remains essential: if bellflowers grow directly into the peony crown, they reduce light and airflow. Leaving a small gap of 20–30 centimetres keeps both plants healthy.

Hydrangeas and bulbs: colour in the background and through the seasons

Hydrangeas as a calm backdrop

Hydrangeas work beautifully behind larger herbaceous peonies. Their rounded flower heads echo the form of peony blooms, but appear at a slightly different time. This creates a natural relay effect through summer.

For this partnership to work, keep the following in mind:

• Do not plant hydrangeas too close behind peonies, or they will cast excessive shade.
• Choose varieties that tolerate sun and cope well with ordinary garden soil.
• Position larger shrubs to one side instead, helping to maintain air circulation in the border.

Iris, alliums and daylilies: perfectly timed flowering

With thoughtful planning, you can enjoy a border that flowers almost without interruption:

Plant	Typical flowering period	Role in the peony border
Bearded iris	Early to mid-spring	Opens the season before peonies properly begin
Peonies	Late April to June (depending on variety)	The peak of the display, with large individual flowers
Allium	Late spring to early summer	Rounded accents among peonies, also serving as a protective plant
Daylilies	High summer	Take over as peonies retreat and their foliage gradually declines

This combination ensures the border remains interesting for months, rather than looking attractive for only a few weeks.

Lavender as a fragrant protective barrier

Lavender is much more than a scented plant for creating a holiday feel in the garden. Its growing requirements are an ideal match for peonies: plenty of sun, free-draining soil and no waterlogging.

“Lavender around peonies acts like a natural protective belt: attractive to look at and unwelcome to many pests.”

Its powerful fragrance deters a range of unwanted visitors, including:

• Mosquitoes
• Flies
• Fleas
• Moths
• Deer, which are reluctant to pass through strongly scented areas

Combined with alliums, this creates a double effect. The decorative ornamental onions provide purple or white spherical blooms, while their onion-like scent is disliked by many insects. Together, they form an almost invisible defensive ring around the peony border.

Which planting partners should keep their distance

Not every plant that looks suitable is automatically a good immediate neighbour. Particularly vigorous species can quite literally deprive peonies of air.

Potentially troublesome choices include:

• Tall ornamental grasses with strong root systems planted directly beside the clump,
• Perennials that require permanently wet soil,
• Very wide-spreading shrubs in the immediate area.

Such plants increase the risk of damp conditions and force peonies into shade. If you enjoy amphibious plants or bog perennials, it is better to place them in a separate part of the garden or create a clear divide, for example with a path or wall.

Practical tips for a long-lasting peony border

Plan generous spacing from the outset

At planting time, peonies often look deceptively small. Many gardeners then make the mistake of filling the gaps too tightly with other perennials. It is better to plan for the final size: a mature plant can easily reach 80 centimetres across.

A tried-and-tested layout is as follows:

• Place a peony clump in the centre of a border.
• Plant low-growing companions such as lady’s mantle or bellflowers 40–60 centimetres away.
• Set lavender, ornamental alliums and, where appropriate, small shrubs further out.

Soil care without stressing the perennials

Because peonies remain in place permanently, the soil around them should be disturbed as little as possible. Deep digging immediately around the crown weakens the plants. A gentler approach is better:

• In spring, spread a little well-rotted compost around each plant without digging it in.
• Remove weeds carefully by hand rather than hoeing close to the crown.
• Apply a thin mulch of fine material, such as lawn clippings left to dry first, over bare soil without smothering the root area.

Additional planting combinations and added benefits

Gardeners who want to consider pollinators as well as appearance can place insect-friendly perennials between peonies and lavender. Catmint, sage and coneflowers attract bees and bumblebees in large numbers. The abundance of flowers then looks spectacular not only to people, but also becomes an important garden buffet.

It is also worth considering fading foliage. Peonies gradually retreat over the course of summer. Daylilies, cranesbills or low-growing perennial phlox varieties planted in front can elegantly conceal browning leaves. This keeps the border neat and well cared for without the need for constant cutting back.

Anyone planning a new garden or refreshing an old border can save considerable work by incorporating these principles from the start: plenty of sunshine, airy planting distances, dry and warm-loving partners such as lavender, and decorative protective plants such as alliums. A few peony clumps will then become an almost overflowing focal point year after year – without complicated care routines.