Garden Vegetable Garden Ideas 23 Flowers You Should Never Plant Next to Your Vegetables—Here's Why These flowers can inhibit the growth of your vegetables, as well as spread diseases and unwanted pests. By Madeline Buiano Madeline Buiano Madeline Buiano is an associate editor at MarthaStewart.com, sharing her knowledge on a range of topics—from gardening and cleaning to home and pets. She has five years of writing and editing experience in the digital publishing industry. Editorial Guidelines Published on June 5, 2024 Close Photo: Getty Images In many instances growing flowers next to your vegetables can boost the vitality of both plants—a gardening technique called companion planting. On the other hand, some flowers can negatively affect your vegetable plants, rendering them inedible. Whether they contain toxic compounds that are dangerous to ingest or are susceptible to harmful pests and diseases, there are the flowers experts say you should never plant next to your vegetables. Linda Langelo, horticulture specialist at Colorado State University, where she specializes in various gardening topics, including herbaceous plants, vegetables and vegetable insects, landscape design, and rock gardening. Carrie Spoonemore, co-creator of Park Seed's From Seed to Spoon app, an app that's designed to make planning a garden easier. 10 Plants You Should Never Grow Next to Your Tomatoes 01 of 23 Sunflowers Westend61 / Getty Images While sunflowers are a beautiful addition to any garden, they don’t play nicely with vegetables. “The sunflower seeds have a toxin that stunts growth once released in the soil,” says Langelo. “Planting them next to pole beans or potatoes will stunt their growth.” Additionally, sunflowers attract unwanted garden pests like aphids, whiteflies, and squirrels. 02 of 23 New England Aster Kevin Dutton / Getty Images New England aster (Aster novae-angliae) attracts the aster leafhopper (Macrosteles quadrilineatus), an insect that feeds on its leaves and can release a pathogen into the plant, says Langelo. This pathogen can cause malformed and bitter-tasting garlic, carrots, and onion plants, so it's best to keep it far away. 03 of 23 Oregano tanjica perovic photography / Getty Images Oregano (Origanum vulgare) is a flowering herb that has intense volatile compounds produced in its roots. “These volatile compounds inhibit the growth of neighboring plants,” says Langelo. “The stems and leaves also contain these volatile compounds. Any plant debris left in the garden can continue inhibiting future plant growth." 10 Plants You Should Never Grow Next to Your Tomatoes 04 of 23 Rosemary Correcaminos112 / Getty Images Rosemary (Salvia rosmarinus) is an aromatic flowering herb that contains carnosic acid. “This acid negatively impacts the growth of nearby plants,” says Langelo. “In dry soil conditions, the effect can intensify.” 05 of 23 Oleander Danita Delimont / Gallo Images / Getty Images All parts of oleander (Nerium oleander) are extremely toxic and can contaminate the soil and nearby plants, says Spoonemore. If you plant oleander next to your vegetables, the leaves can drop from the plant and accidentally be brought in with the harvest, says Langelo. 06 of 23 Gladiolus Neil Holmes / Photolibrary / Getty Images Gladiolus is a corm-bearing plant that blooms from August to September. While it is a beautiful addition to the garden, plant it away from legumes, like peas and beans, as it can hinder the growth of these vegetables, says Langelo. 07 of 23 Foxglove aimintang / Getty Images All parts of foxglove (Digitalis purpurea) are toxic, which can make it a risk when planted around vegetables where you may inadvertently come into contact with it during harvest, says Spoonemore. 08 of 23 Sweet Pea Andyd / Getty Images Sweet peas (Lathyrus odoratus) are a bushy climbing annual that resemble garden peas and should be planted away from this vegetable so you don’t confuse the two. “The commercially bred plants are not edible,” says Langelo. “The seed pods are toxic.” 16 Companion Plants You Should Grow Next to Cucumbers—and 7 You Shouldn't 09 of 23 Daffodil Daffodils are associated with luck and unrequited love. Nicolette Wells / Moment / Getty Images Plant daffodils (Narcissus) in a border garden away from vegetables, as this flowering perennial contains alkaloids, a class of organic compounds that can cause convulsions, dizziness, and abdominal upset when ingested, says Langelo. 10 of 23 Creeping Jenny Getty Images Do not plant creeping Jenny (Lysimachia nummularia) as a ground cover in your vegetable garden, as it could spread quickly and take over. “Creeping Jenny has fibrous and shallow roots,” says Langelo. “It can take nutrients and water from the soil easily, robbing other shallow-rooted crops such as spinach, radishes, and broccoli.” 11 of 23 Phlox Amy Mitchell / Getty Images Phlox (Phlox paniculata) is an herbaceous perennial that contains substances that will stop the growth of brassica family members, including kale, cabbage, broccoli, and cauliflower, says Langelo. 12 of 23 Lily of the Valley RiverNorthPhotography / Getty Images Lily of the valley (Convallaria majalis) is highly toxic to humans and animals and can be dangerous if planted near edible crops, says Spoonemore. If you do plant it in your garden, make sure it’s far away from your vegetables so it doesn’t accidentally get added to your harvest. 13 of 23 Ragwort Ed Reschke / Getty Images Ragwort (Jacobaea vulgaris) is a noxious weed that can be toxic if consumed. Additionally, it can attract undesirable insects that can spread to and harm your vegetables, says Spoonemore. 14 of 23 Wisteria Getty Images Wisteria is toxic to humans and pets; therefore, it can be dangerous to grow alongside edible plants. Additionally, wisteria is a fast grower and can overpower nearby plants, says Spoonemore. 15 of 23 Poppy Getty Images Poppies (Papaver ) can harbor diseases, like botrytis and downy mildew, that might spread to vegetable plants, says Spoonemore. 16 of 23 Chrysanthemum Getty Images Chrysanthemum is a beloved fall container plant, but it's best to keep it away from your edibles. "Chrysanthemum releases chemicals that inhibit the growth of some vegetables," says Spoonemore. 17 of 23 Morning Glory YangYin / Getty Images Morning glory (Ipomoea purpurea) spreads rapidly and can choke out vegetable plants when they're grown in close proximity to one another, says Spoonemore. 20 Full-Sun Annuals That Will Add Color to Your Garden 18 of 23 Larkspur happykamill / Getty Images Larkspur (genus Delphinium), a flowering plant in the buttercup family, contains toxic alkaloids, which are dangerous if ingested, says Spoonemore. 19 of 23 Clematis Evgenii Mitroshin / Getty Images Clematis is a climbing plant that looks beautiful trailing fences, pergolas, trellises, and more, but it should be planted away from your vegetables. "Clematis can attract spider mites and aphids," says Spoonemore, adding that the plant itself can be toxic if ingested. 20 of 23 Bleeding Heart Jacky Parker Photography / Getty Images Bleeding heart (Lamprocapnos spectabilis) contains toxins that can be harmful if mistakenly ingested, so it's important to plant it away from your vegetable garden, Spoonemore says. 21 of 23 Angel's Trumpet ntdanai / Getty Images Angel's trumpet (Brugmansia) is highly toxic if ingested by humans or animals, says Spoonemore. Plus, it attracts pests like aphids and spider mites, which can spread to your vegetable crops. 22 of 23 Begonias Jobrestful / Getty Images Begonias are susceptible to powdery mildew and other fungal diseases, which can spread to vegetables, says Spoonemore, adding that this plant also attracts pests like spider mites. 23 of 23 Yarrow aga7ta / Getty Images Yarrow (Achillea millefolium) can be invasive and compete with vegetables for essential resources like nutrients and water. "Yarrow also attracts pests like aphids and spittlebugs," says Spoonemore. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit