14 Plants You Should Never Grow Next to Hydrangeas Keep these plants away from your hydrangeas if you want your flowers to flourish. Close Credit: Masaaki Ohashi / Getty Images Hydrangeas are some of the most beautiful flowering shrubs. Known for their spectacular blooms in a range of colors, they work great in a late summer or early fall garden. However, it turns out that some plants don’t play well with hydrangeas. These plants include other flowers, trees, vegetables, and herbs, many of which prefer other soil types or need different care. Some even emit chemicals that are harmful to hydrangeas and other flowers. Ahead, we spoke to garden experts about which plants to keep away from your hydrangeas to ensure that these showy shrubs thrive. Christine Schaub, host of the home and garden YouTube show Come on Over Andrew Connolly, owner of Little Flower Cottage, a seller of flowers Evan Torchio, expert arborist and founder of Tree Menders How to Grow and Care for Hydrangeas for Beautiful Blooms Every Year, According to Experts 01 of 14 Thyme Credit: Westend61 / Getty Images A woody herb, thyme prefers dry soil, the opposite of what hydrangeas like. "Thyme is often drought-tolerant and wilts in the kind of moisture hydrangeas crave," says Christine Schaub, host of the YouTube show Come on Over. As an herb, thyme also tends to thrive in the sunniest of sunny locations, something tender hydrangea leaves reject, she says. 02 of 14 Black Walnut Credit: florentina georgescu photography / Getty Images This tree produces juglone, a chemical harmful to many plants. "Specifically, juglone stunts the growth of hydrangeas by stopping water uptake," says Andrew Connolly, owner of Little Flower Cottage, a seller of flowers. 7 Mistakes You're Making With Your Hydrangeas—and How to Avoid Them 03 of 14 Eucalyptus Credit: Getty Images Eucalyptus trees don’t do well with hydrangeas. "Eucalyptus are heavy feeders and can deplete the soil of the most essential nutrients," says Connolly. Thus, the hydrangeas will become malnourished next to the eucalyptus and might not be able to flower. What to Do if Your Hydrangeas Aren't Blooming 04 of 14 Lavender Credit: Isabel Pavia / Getty Images Never plant lavender next to hydrangeas. "Lavender is notoriously finicky about soil moisture, humidity, and sun," says Schaub. Since it hails from the Mediterranean, lavender prefers dry, rocky, sandy conditions, conditions a hydrangea plant can’t cope with. "And lavender will let you know it’s unhappy by turning yellow, then brown, and the hollow stem will snap right off," she says. 05 of 14 Daffodils Credit: Jacky Parker Photography / Getty Images Daffodils can be toxic to other plants. "Their roots secret a substance that inhibits the growth of any neighboring plants," says Connolly. 06 of 14 Marigolds Credit: Philippe S. Giraud / Getty Images While a great companion plant for many herbs and vegetables, marigolds do not get along with hydrangeas. "These orange-toned beauties want sun all day, every day. And they like their 'feet' in drier conditions," says Schaub. If placed in moist ground that hydrangeas like, your marigolds will droop, turn yellow, and eventually die. 07 of 14 Bamboo Credit: Westend61 / Getty Images Technically a species of grass, bamboo shouldn’t grow next to just any plant. "Bamboo can cast too much shade, depriving hydrangeas of the sunlight they need," says Evan Torchio, founder of Tree Menders. Plus, certain bamboo varieties are considered invasive, as they spread aggressively and therefore should be kept in a confined space like a concrete planter away from native plants. 10 Patio Plants That Thrive in Pots and Containers 08 of 14 Limelight Hydrangea Credit: Olga Seifutdinova / Getty Images Surprisingly, not all hydrangea varieties get along. "Planting different hydrangea varieties too close together can lead to cross-pollination issues," says Connolly. And placing too many different hydrangeas on top of each other can impact the color and intensity of their flowers, especially in closely related hydrangea species. A Visual Guide to the Most Popular Types of Hydrangeas 09 of 14 Roses Credit: ChamilleWhite / Getty Images Roses can compete with hydrangeas for nutrients and water. This is particularly true in small gardens. "Additionally, some rose varieties may prefer different soil conditions than hydrangeas," says Torchio. 10 of 14 Lilac Credit: Elena Popova / Getty Images A flowering bush, lilac is an aggressive grower. "It can quickly outcompete other plants for resources," says Torchio. Plus, these flowers prefer well-drained soil, the opposite of what hydrangeas like. Why Your Hydrangeas Are Drooping—Plus Expert Tips on How to Revive Them 11 of 14 Anemone Credit: Getty / EyeEm Anemone blooms in mid-to-late summer just like hydrangeas, but these flowers should never be planted together. Hydrangeas grow big, towering over this low-lying plant. "If the anemone base is too shaded, it will not bloom, and then you’ll miss the best part of this hardy plant," says Schaub. 8 Ways to Get More Hydrangea Flowers on Your Shrubs—and Keep Them Blooming 12 of 14 Garlic Credit: Aksana Zavadskaya / Getty Images Garlic and hydrangeas don’t get along. "While not commonly planted in ornamental gardens, garlic can affect the growth of floral plants like hydrangeas," says Connolly. This is because garlic releases allelopathic chemicals that can harm flowers. 13 of 14 Sunflowers Credit: Jacky Parker Photography / Getty Images Known for their height, sunflowers can shade out hydrangeas. "Also, some studies suggest that sunflowers may have allelopathic properties, releasing chemicals that can inhibit the growth of nearby plants," says Torchio. 15 Plants You Should Always Grow Next to Hydrangeas 14 of 14 Sage Credit: P A Thompson / Getty Images Sage and hydrangeas are not a good mix. Sage thrives in dry, well-drained soil and full sun, while hydrangeas prefer partial shade and moist soil. When planted near each other, sage may suffer from too much moisture, while hydrangeas could struggle with a lack of nutrients and competition for root space. Explore more: Garden Flower Gardens