Brittany Hambleton

Brittany Hambleton

July 30, 2024

Bad Neighbors: 11 Plant Pairs Never to Grow Side by Side

As the warm weather approaches, gardeners across the country are starting to plan their flower beds and vegetable patches in anticipation of the garden-planting season. Whether you’re a seasoned gardener, or if this is the first year you’ve decided to get outside and get your hands dirty, you’ll want to make sure that you’re doing everything you can to ensure your garden’s success.

Many gardeners will use the principles of companion planting to make sure they’re putting plants together that will help each other to thrive. It is equally as important, however, that you consider which plants should not be planted together, or else your garden could fail. 

Read the Tags Carefully

Handmade paper price tag or blank tag for your label lying on the azalea leaves.
Source: Shutterstock

Consider the following rules of “non-companion” plants, as well as plants that don’t grow well together, before you take your trowel to the soil. Different flowers or plants may require vastly different growing conditions in order to thrive. This information will be included on their tags, and it is important that you read this information carefully and heed their advice. 

If you put two plants together that require different growing conditions, they both could suffer because you aren’t able to meet their needs. Butterfly weed, for example, does well with plenty of sunlight and dry soil, while impatiens need lots of water. Many gardeners focus on which flowers would look nice together, without considering their growing requirements, so read those tags before you make any decisions [1].

Bad pairing: butterfly weed and impatiens

Read More: 4 Houseplants You Can Easily Propagate From Cuttings

Careful with your Aromatics

Ocimum basilicum. Thai basil, spice and medicinal plant.
Source: Shutterstock

Some vegetables, namely cucumbers, do not grow well near aromatic herbs like basil, rosemary, sage, and marjoram. These herb’s strong scents and flavors tend to change the taste of the cucumbers, which may not be desirable. On the other hand, cucumbers do tend to do well next to dill, because it attracts hoverflies and wasps, which are beneficial to cucumbers. Ask at your local garden shop which herbs and which plants go well together, and if you’re uncertain, you can always plant your herbs separately in pots [1].

Bad pairing: cucumber and basil

Bushes Should be the Same Height

Tropical plant flower bush tree isolated on white background with clipping path.
Source: Shutterstock

When your bushes aren’t the same height, the taller of the two could cast too much shade on the other. This could cause the smaller plant to thin out over time and die. Make sure that you speak with the professionals at your local garden shop if you are uncertain how tall your bushes will grow, and plant accordingly [1].

Bad pairing: Leyland Cypress and Spiraea

Legumes Don’t Like Onions

Glycine max, soybean, soya bean sprout growing soybeans on an industrial scale. Products for vegetarians. Agricultural soy plantation on sunny day. An untreated field with weeds.
Source: Shutterstock

In the world of gardening, leguminous plants, like beans and peas, and plants in the onion family, like garlic, chives, and leeks, are like the Montagues and the Capulets. They do not get along. Legumes, in general, are quite picky, as they also don’t do well next to plants in the cabbage family, like broccoli, cauliflower, and kale [1].

Bad pairing: beans and garlic

Take Note of the Growth Rate

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“If one plant grows quickly, and its neighbor grows slowly, the faster plant will take over,” says  Rex Bishop, director of technical education for the National Association of Landscape Professionals [1]. You should speak with your local gardening professional ask about growth rates, and match plants according to their speed.

Bad pairing: Silverberry and boxwood

Heavy Feeders Should be Kept Separate

Beautiful red ripe cherry tomatoes grown in a greenhouse
Source: Shutterstock

You don’t want your plants competing for the same nutrients. When you have two plants next to each other that are both heavy feeders, as is the case with tomatoes and corn, they will both suffer because they can’t get all the nutrients they need. Tomatoes and corn also share a common pest, which could end up killing them both if one plant becomes infested [1].

Bad pairing: tomatoes and corn

Don’t Plant Too Many of the Same Thing

Farmer giving granulated fertilizer to young tomato plants. Hand in glove holding shovel and fertilize seedling in organic garden.
Source: Shutterstock

Just like tomatoes and corn share a common pest, two of the same plant, of course, will have the same problem. If you plant too much of the same thing, you risk losing your entire flower bed if one plant gets sick. Try to include a variety of plants in your garden to prevent the growth of fungus and pests [1]

Bad pairing: Gardenias and gardenias, impatiens and impatiens, etc.

Read More: 15 Medicinal Plants That Can Easily Be Grown In Your Yard

Allelopathic Plants: Good for Some, Not for Others.

agricultural business.sunflower oil production.sunflower harvest.sunflower field.farming and agronomy in ukraine.sunflower promotion.yellow field.young harvest.sunflowers wallpaper. big field.summer
Source: Shutterstock

The term allelopathy refers to the beneficial or harmful effects that one plant has over another [2]. Some plants are good for each other, and some are not. Sunflowers, for example, are great at preventing weeds from growing between crops, however, their seeds, which end up dropping into the soil below, release toxins that inhibit the growth of potatoes and pole beans. If you want to plant sunflowers, be sure to place them at least one foot away from your vegetable garden [1].

Bad pairing: sunflowers and potatoes

Not Everyone Likes the Shade

Thoroughbred horses grazing at sunset in a field.
Source: Shutterstock

If you were planning on covering your lawn with leafy turfgrass like bluegrass, fescue, and ryegrass, but your yard contains a number of shade trees like maples, oaks, and spruces, you may want to reconsider. Plants that grow directly below those trees don’t get much sunlight or moisture, and while some may thrive in those conditions, turfgrass suffers.

“Turfgrasses require more fertilization because they are leafier and constantly getting pruned by mowing and other activities,” says Bishop. “The roots of the tree take up water and nutrients at the same level in the soil as turfgrass roots, so they struggle.” [1]

Bad pairing: Turfgrass and shade trees

Some Plants Attract Pests

young cabbage grows in the farmer field, growing cabbage in the open field. agricultural business
Source: Shutterstock

This includes all vegetables in the cabbage family, including kale and broccoli. These plants attract pests that inhibit the strawberry’s growth. Make sure you know what kinds of pests your plants may attract, and plan accordingly [1].

Bad pairing: strawberries and cabbage

Black Walnuts Vs. Everybody

a closeup of a Black Walnut tree trunk surrounded with its leaves
Source: Shutterstock

Black walnut trees are notorious among gardeners for killing just about every plant around them. This is because their nuts, hulls, roots, leaves, and stems contain a chemical called juglone that appears to be lethal to plants. If you have one of these trees on your property, talk to your local gardening expert about what plants might be able to survive near them, but don’t attempt to plant an entire garden in its vicinity [1].

Companion Planting for a Successful Garden

Unripe cluster of green plum roma tomatoes growing in a permaculture style garden bed, with companion planting of marigold and calendula flowers, to attract pollinators and detract garden pests.
Source: Shutterstock

Companion planting has been used by farmers for generations and is the secret to a successful garden. Pairing plants that benefit each other is a great way to enhance your garden’s productivity without the use of chemicals or fertilizers [3]. This spring, before you begin preparing your garden for planting, consider what your climate and soil are like, and ask at your local garden shop which plants will work best together under those conditions. We try so often to outsmart Mother Nature, but if we instead try to work with it, we will see much greater success.

Read More: Use These 5 Plants to Help Calm Your Nerves and Have a More Restful Sleep

Sources

  1. https://www.bobvila.com/slideshow/bad-neighbors-11-plant-pairs-never-to-grow-side-by-side-51113#butterfly-weed-and-impatiens
  2. https://edis.ifas.ufl.edu/hs186
  3. https://www.agriculture.vsu.edu/files/docs/cooperative-extension/companion-planting-in-gardening.pdf