Here are 12 plants that should never be planted next to each other in your garden.

With spring officially here, it's the perfect time to start planning your garden. You may already have some ideas for plants you'd like to grow, but it's important to remember that some plants simply don’t get along. Even if you provide them with the best growing conditions, like warring neighbors, these plants may not thrive together. Here’s a list of plants to avoid growing next to each other.

Drought-Resistant Plants and Moisture-Dependent Plants

If you're planning to grow a diverse range of plants, be cautious when planting drought-tolerant plants alongside moisture-loving varieties. As per Bliss Bendall, NYBG-certified horticulturist, this combination could lead to root rot in your drought-resistant plants. It's best to keep these two plant types as far apart as possible.

Gardenias and Almost Anything Else

Bendall advises against planting gardenias near any other plants. While they are beautiful, gardenias are prone to spreading diseases. 'When one gardenia becomes ill, the rest are likely to follow and perish. It’s best to plant them separately.'

Garlic and Other Vegetables

Garlic is a flavorful addition to many dishes but doesn’t benefit nearby plants in your garden. Bendall points out, 'Garlic releases sulfur into the soil, which can inhibit the growth of legumes, beans, peas, and leafy greens like parsley. Garlic is better planted alone or with other plants that can tolerate sulfur.'

Knockout Roses and Annabelle Hydrangeas

Knockout Roses and Annabelle Hydrangeas may look stunning together in a bouquet, but they’re not the best companions in a garden setting, according to Sara Downing, Principal at OvS. 'When selecting plants to share space, both aesthetic and ecological factors must be considered. Plants should be similar in key aspects—soil preferences, USDA hardiness zone, light requirements, and most importantly, water needs. Roses prefer full sun, while most hydrangeas favor shade, which means they wouldn't thrive together.'

Downing also points out that these flowers grow differently in various ways. 'They have different foliage textures, bloom impacts, overall forms, and root systems, which prevents them from competing for space. Essentially, they need to complement each other. Both roses and hydrangeas are shrubs that desire to dominate the same area, and they can even compete visually with their striking, ornamental blooms.'

Tomatoes and Potatoes

Although tomatoes and potatoes are a delicious pair on a plate, they shouldn’t share the same soil. Sara Abbass, owner of Sara Mairead Landscape Design, suggests growing tomatoes away from potatoes, as well as cabbage and broccoli. 'These plants compete for the same nutrients! Tomatoes and potatoes are from the same plant family, and they not only fight for resources but are also vulnerable to the same diseases, such as blight,' she explains. 'Brassica plants like cabbage and broccoli are also prone to fungal diseases similar to those affecting tomatoes, so they should be spaced apart to protect the crops.'

Mint and Everything Else

Mint adds a refreshing touch to everything from water to cocktails to various dishes, making it an exciting herb to grow. However, Abbass recommends planting mint in containers. 'Mint is highly invasive and can easily take over a garden, competing with perennials and even entangling in shrubs, pushing out any plants nearby.'

Monarda and Cucumbers

Cucumbers are a wonderful addition to any garden, but they shouldn’t be planted near Monarda. Abbass explains, 'Monarda is a fantastic pollinator attractor, but it's also vulnerable to powdery mildew, a persistent fungal disease that can affect cucumbers as well.' She suggests planting Monarda in a large container to enjoy its pollinator benefits or choosing the more disease-resistant Monarda bradburiana.