13 Plants You Should Not Grow with Peonies

Growing peonies can be a delight, but it's essential to choose the right companions to ensure their beauty and health thrive.

Many plants can actually harm or compete with peonies for resources, so it's best to avoid planting them together.

Some plants, like lavender, can be too competitive for water and nutrients, potentially stunting peony growth.

On the other hand, there are some plants that can benefit from peonies' shade, such as roses, which can be planted nearby to create a stunning combination.

Peonies don't like competition, and they need their space and good air circulation to prevent diseases.

Plants that spread quickly, like Japanese anemone and artemisia, can crowd out peonies and increase the risk of powdery mildew. To avoid this, plant them far apart and be prepared to continuously pull and prune them to keep them under control.

Tall varieties of ornamental grasses can block sunlight that peonies need, and their sprawling roots compete with peony roots for water and nutrients. Large trees with extensive root systems, like maples and walnuts, also compete for moisture and nutrients, and can even stunt peony growth due to the chemical juglone released by walnut trees.

For more insights, see: Companion Plants for Peach Trees

Here are some plants to avoid planting with peonies:

Groundcover Roses are a great choice for a low-maintenance, flowering groundcover that can thrive in partial shade to full sun. They're also a good option for areas with poor soil.

Some Groundcover Roses can grow quite dense, making them an excellent choice for erosion control on slopes. They can also be used to cover large areas quickly.

These roses have a moderate growth rate, with some varieties growing up to 3 feet in a single season. They're also relatively pest- and disease-free.

Groundcover Roses can be pruned in late winter or early spring to maintain their shape and promote new growth. They can also be used as a living mulch to suppress weeds.

They come in a variety of colors, including pink, white, and red, and can be used to add a pop of color to your garden. Some varieties even have a sweet fragrance.

Planting late-emerging perennials like hostas directly with peonies can be a problem. This is because by the time hostas emerge, peony foliage is already unfurling.

Hostas are often planted around peonies to "hide the bare legs" after blooming, but this can lead to damaged peony foliage.

Some plants are just too competitive to grow alongside peonies. Lilacs, for example, will spread their roots and suckers everywhere, forming colonies that can outcompete peonies for space and sunlight.

Mint and other members of the mint family are notorious for their aggressive spreading habits, sending underground runners that can starve peonies of nutrients and water. They're nearly impossible to remove without disturbing the peonies.

Wisteria and other aggressive vines can strangle peony stems and create dense shade that prevents blooming. Their underground runners can also disrupt peony roots, making them nearly impossible to remove once established.

Some plants are prolific self-seeders, producing thousands of seedlings that can create a maintenance nightmare and competition for peonies. Alliums, bearded iris, and heuchera are just a few examples of plants that can outcompete peonies.

Here are some examples of plants that are known to be competitive and aggressive with peonies:

Lilacs are notorious for their ability to outcompete other plants for resources, especially in woodland edges and hedgerows.

Their deep taproots allow them to access water deep in the soil, giving them an advantage over plants with shallower roots.

Lilacs can grow quite tall, up to 30 feet, and their dense foliage makes it difficult for other plants to receive enough sunlight.

They also produce a chemical that inhibits the growth of nearby plants, further increasing their competitive advantage.

Explore further: How Deep Do You Plant Peonies

Tall Ornamental Grasses are not a good match for peonies. Their aggressive, dense root systems outcompete peonies, creating a challenging environment for them to thrive.

One of the biggest issues with tall ornamental grasses is their ability to create too much shade when fully grown. This can be detrimental to peonies, which require full sun to partial shade.

Tall ornamental grasses also drop seeds that can germinate throughout your peony bed, leading to a mess and potentially overcrowding the area. This can be difficult to control and may require regular maintenance.

Many tall ornamental grasses require division every few years, disturbing nearby peonies in the process. This can be a stressful experience for the plants and may cause them to become diseased or damaged.

Some key differences between tall ornamental grasses and peonies include:

Aggressive self-seeders can be a real challenge in the garden, especially when they're competing with peonies for space and resources. Prolific self-seeders like verbena bonariensis can produce thousands of seedlings, creating a maintenance nightmare.

These plants can weaken your peonies substantially, making them more vulnerable to disease and pests. In fact, I recall a garden where verbena bonariensis was allowed to spread freely, and it significantly impacted the health of the peonies.

Some aggressive self-seeders to be aware of include:

By being aware of these aggressive self-seeders, you can take steps to prevent them from overpowering your peonies and ensure a healthy, thriving garden.

Wisteria and other aggressive vines can be a nightmare to deal with in the garden. They can literally strangle peony stems, making it difficult for the plants to thrive.

Vines like wisteria create dense shade that prevents blooming, which is a major bummer for any plant lover. This is especially true for plants like peonies that rely on sunlight to produce beautiful flowers.

Underground runners from aggressive vines can disrupt peony roots, causing even more problems for the plant. It's like a silent invasion, sneaking up on your poor peonies and causing chaos.

Removing these aggressive vines once they're established can be nearly impossible, so it's best to catch them early. Wisteria, in particular, is notorious for its ability to outcompete and outlast other plants.

Here are some key facts about aggressive vines like wisteria:

Strawberries, tulips, and roses are all susceptible to botrytis blight, making them poor companions for peonies. This fungal disease can spread rapidly in wet conditions and persist in soil for years.

Botrytis blight can cause peonies to develop blackened buds that never open. If you're planning to plant these species together, be aware of the potential risks.

If you do decide to plant strawberries, tulips, and roses near peonies, make sure to keep a close eye on the plants and take action quickly if you notice any signs of the disease.

Here are some plants that are particularly problematic to grow with peonies due to their susceptibility to botrytis blight:

Planting trees and shrubs near peonies can be a recipe for disaster. Large trees like maples can have extensive root systems that steal nutrients and moisture from peonies, reducing bloom production dramatically.

The shade created by these trees can also harbor diseases that affect peonies, and falling branches or debris can damage fragile peony shoots. It's essential to keep peonies at least 15 feet away from large trees like maples.

Some trees, like walnut trees, produce juglone, a natural toxin that suppresses the growth of many plants, including peonies. This can lead to stunted growth, reduced bloom production, and yellowing leaves.

Here are some trees and shrubs to avoid planting near peonies:

Walnut trees are a major no-go when it comes to planting near peonies. They produce juglone, a natural toxin that can stunt peony growth and even cause yellowing leaves and general decline.

Juglone can persist in the soil even after the tree is removed, so it's best to steer clear of walnut trees altogether. This is especially true for black walnut trees, which are notorious for their juglone production.

Here are some effects of juglone on peonies:

Other trees with extensive root systems, like maples, can also compete with peonies for moisture and nutrients, making it harder for them to thrive. So, it's best to plant peonies far away from these types of trees.

River Birches are a popular choice for landscaping due to their two-toned leaves and damage-resistant branches.

Their canopy can spread as wide as 40 feet, making them a great option for shade.

However, they host around 300 species of lepidoptera, which can be a problem if you have other plants nearby.

Larvae from these insects can devour your peonies if given the chance, so it's best to keep them away.

This is just one reason to exercise caution when planting river birches in your garden.

When planting deep-rooted vegetables near trees and shrubs, it's essential to consider their impact on the surrounding environment. Different watering needs can create stress for peonies, making them less likely to thrive.

If you're planning to grow vegetables like carrots or beets near peonies, be aware that their root zones are easily disturbed. This can cause damage to the peony roots and potentially harm the plant.

Frequent fertilizing of vegetables can also burn peony roots, so it's crucial to fertilize carefully and avoid over-fertilizing.