Creating a beautiful flower garden takes planning, preparation and time. Putting plants together is also about more than aesthetics. Knowing the perennials you should never plant together will help your flower beds to thrive.

Plants like a variety of conditions, ranging from sunny to shady spots, damp or dry soil. Knowing the preferences of certain plants will help you to make informed decisions, knowing what to put together and what to keep apart for successful combinations.

In order for you to select the best perennials for your flower beds and borders, we’ve asked horticulturalists and gardening experts to highlight some tempting but unsuitable pairings and the reasons why they shouldn’t be planted together.

(Image credit: Getty Images/CoinUp)

Perennials you should never plant together



Planning, preparation, and time are essential for creating a beautiful flower garden. Combining plants goes beyond aesthetics and requires knowledge of which perennials should not be planted together to ensure the success of your flower beds.

Plants have varying preferences for conditions such as sunlight, shade, and soil moisture. Understanding these preferences will help you make informed decisions about which plants to pair and which to keep apart for optimal growth.

To assist you in selecting the best perennials for your flower beds and borders, we consulted horticulturalists and gardening experts to identify unsuitable pairings and explain why they should not be planted together.

(Image credit: Getty Images/CoinUp)

Perennials you should never plant together

‘Combining regionally-appropriate, site-appropriate plants is key to successful planting and supporting your local environment,’ says ecological landscape designer, Kim Eierman, founder of EcoBeneficial.

‘It’s a good practice to combine native plants that naturally occur in the same plant community, that have evolved to share a common environment in nature.

‘For example, if you have a wet, sunny area, you could reflect a regional wet meadow plant community, with plants such as Eutrochium species (Joe Pyeweeds), Verbena hastata (Common Vervain), and Veronia noveboracencis (New York Ironweed).’

1. Milkweed varieties

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Native milkweeds (Asclepias species) are important plants for pollinators, especially for the endangered monarch butterflies. While they make a lovely addition to a garden, it’s crucial to understand that not all types of milkweed can be planted together.

‘Native milkweeds are highly valuable nectar plants for many types of pollinators,’ says Kim. ‘There are numerous milkweed species native to North America, each with unique characteristics. It’s advisable to plant multiple species of native milkweeds, but consider the average soil moisture in your landscape.’

‘For instance, Asclepias incarnata (Swamp Milkweed) thrives in moist to wet soils, while Asclepias verticillata (Whorled Milkweed) prefers drier soils. Select milkweeds native to your region and suitable for your site conditions.’

Milkweed seeds are available from Walmart.

Kim Eierman

Kim Eierman is the Founder of EcoBeneficial LLC. She is an ecological landscape designer and environmental horticulturist specializing in native plants. Based in New York, Kim teaches at the New York Botanical Garden, the Brooklyn Botanic Garden, The Native Plant Center, and the Massachusetts Horticultural Society.

2. Goldenrod varieties

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If you’re interested in creating a garden for pollinators, native goldenrods are a beautiful perennial family to consider. However, not all goldenrods will coexist harmoniously.

‘Native goldenrods (Solidago species) are keystone species that provide valuable forage for pollinators and serve as larval host plants for many butterflies and moths,’ says Kim.

‘While planting multiple species of goldenrods is beneficial, it’s important to choose carefully. Aggressive native goldenrods may outcompete other species. For example, Solidago canadensis (Canada Goldenrod) is beneficial but aggressive, best suited for large spaces, not small home landscapes.

Solidago caesia (Blue-stemmed Goldenrod) is a well-behaved plant, incompatible with a vigorous perennial like Canada Goldenrod.’

Canada goldenrod seeds are available from Walmart.

3. Anemones and Wood Poppies

(Image credit: Getty Images / Brian Woolman / Maria Mosolova)

If you’re considering planting a wildflower meadow, you might think of including poppies and anemones for their colorful blooms. However, some flowering perennials, like Anemone canadensis and Stylophorum diphyllum (Wood Poppy), are incompatible due to allelopathic properties.

‘Some plants release biochemicals that inhibit the growth of other plants around them,’ explains Kim. ‘Anemone canadensis and other native Anemone species are allelopathic and unsuitable for planting together.

‘While it may seem appealing to plant Wood Poppy followed by Anemone canadensis, it’s not advisable. Anemone canadensis is aggressive and allelopathic, outcompeting other plants.’

4. Russian sage and Hostas

(Image credit: Getty Images / agathchen / Darell Gulin)

Russian sage, also known as Salvia yangii, is a popular perennial for borders due to its lilac flowers and low-maintenance nature. While it attracts pollinators, it should not be planted with hostas.

‘Russian sage thrives in full sun and dry soil conditions,’ says Kat Aul Cervoni, landscape designer and founder of Staghorn Living. ‘Hostas may struggle in these conditions and are better suited next to astilbe, ferns, or heuchera.’

‘Russian sage may struggle in shady conditions and damp soil. Consider pairing it with prairie dropseed grass if you want greenery next to it.’

Consider this Russian sage from Nature Hills for your borders or container gardening ideas.

Kat Aul Cervoni

Landscape designer, Katherine “Kat” Aul Cervoni, is the founder and principal of Staghorn Living. Kat