Laura Walters
Are your hydrangeas are struggling to thrive, despite doing everything right to care for them? The plants growing nearby could be the cause of your hydrangea hardship. There are certain plants that just don't play well with these beautiful blooming shrubs.
Hydrangeas generally thrive in partial shade and in well-drained, rich soil that retains moisture. In these conditions, hydrangeas are undemanding. However, they might not do so well if you grow them with other plants that need different growing conditions or plant them next to a species that actually harms them. Choosing the wrong planting location can be one of the worst hydrangea care mistakes you can make.
So keep your favorite flowering bushes healthy and happy and avoid these not-so-nice hydrangea companion plants. Plus, I'll share some better alternatives to plant near to your hydrangeas instead.
1. Lavender
Another popular garden plant like hydrangeas, lavender is a low-growing, shrubby herb with characteristically fragrant and colorful flowers. This plant might look nice growing under a larger hydrangea, but it is not a good pairing.
The problem is that when growing hydrangeas and lavender, they need drastically different conditions to thrive and be healthy. Lavender flourishes in full sun, hot weather, and dry conditions. Either the lavender or the hydrangea will suffer if grown together. Save lavender for containers or another area of the garden.
Instead grow a lavender-blooming hosta, like 'Shadowland Diamond Lake' from Proven Winners at Home Depot, which has much more similar growing needs to water-loving hydrangeas.
2. Sunflowers
Sunflowers are similar to lavender in that they need full sun to grow and bloom. Most hydrangeas will wilt and suffer in full sun, so they shouldn’t be planted together. Some types of hydrangeas, like panicle hydrangea varieties, actually prefer more sun. But sunflowers are tall and might shade them too much.
Another reason to keep sunflowers away from hydrangeas is that they are allelopathic. This means they produce and give off chemicals that can harm other plants growing near them. Sunflowers are best grown together and not too close to other plants.
For a sunny pop of color next to your hydrangeas, grow a 'Stella D'Oro' daylily from Home Depot. It will rebloom all summer and give you an even better show than sunflowers.
3. Forsythia
Forsythia blooms vigorously with small, bright yellow flowers in spring, ahead of many other flowering plants. While it might be tempting to plant them near hydrangeas to stagger blooms and get flowers from spring through fall, this isn't a good idea.
Like sunflowers, forsythias are allelopathic. They can harm hydrangeas planted nearby. To enjoy yellow spring flowers followed by summer hydrangeas, plant these two flowering shrubs in different areas of the garden.
Another option is to grow a native spice bush, which you can find on Amazon.
4. Daffodils
Spring-flowering bulbs under a summer-blooming shrub might seem like a good idea, but this pairing won’t work well. Daffodils are allelopathic as well. They also need drier soil than hydrangeas. Either your hydrangeas will suffer from not getting enough water or your daffodil bulbs will rot due to excessive moisture in the soil.
For a burst of early spring blooms, combine your hydrangeas with celandine poppies from the Gardening Know How Shop instead. These knockout native flowers love moist soil, just like hydrangeas.
5. Black Walnut Trees
While some of the other plants on this list are allelopathic and can release harmful chemicals, black walnut trees are more dangerous than the rest. They release a chemical called juglone, which inhibits the growth of many plants, including hydrangeas.
Another reason to keep hydrangeas out of the reach of a black walnut tree is that they won’t grow well in the deep shade of a tree. To avoid both issues, keep hydrangeas at least 60 feet (18 m) from any black walnut. Of all hydrangea types, smooth hydrangea is most able to tolerate the toxic effects of juglone.
You can explore a variety of different smooth hydrangeas for sale at the Home Depot.
6. Willows
It’s best to avoid planting hydrangeas too close to any large tree, as the shade can be too much to support good growth. While black walnuts are a particular problem because of juglone, willow trees are an issue because of water and nutrients.
Willows grow fast and are heavy feeders. They take a lot of nutrients out of the soil and also need a significant amount of water. Plant willows next to a pond or stream, but not with your hydrangeas, which will suffer from a lack of water and nutrients absorbed by the willow.
Instead, pair your hydrangea with an easy-going weeping redbud tree, which you can order from Fast Growing Trees. This North American native can grow just about anywhere and it provides a dazzling display of purple blooms in spring.
7. Roses
If you love the cottage garden look of hydrangeas, you probably also like roses. Unfortunately, these two do not grow well together. One reason is that they have different needs for sunlight, soil, and water. Also, roses tend to be water and nutrient-hungry. They can outcompete your hydrangeas, causing shrubs to suffer from poor growth.
Instead of growing these classic garden diva, choose one of the many different flowers that look like roses. Peonies are a great alternative for big, showy blooms. Shop bare root peonies from Burpee to plant in fall for stunning flowers next spring.
8. Raspberries
Raspberries are fun to grow. They grow readily and vigorously in the right conditions and provide a harvest of tasty berries in early summer. The problem with raspberries is that they grow aggressively and can quickly crowd out other plants, including hydrangeas.
To enjoy the fruits of these canes while managing their spread, plant raspberries in a dedicated area of the garden. You can keep an eye on them and thin them out as needed.
For more a compact habit, try growing blueberries instead. These acid-loving fruit bushes are perfect to plant next to blue hydrangea varieties as they both need soil with a low pH to thrive. Explore blueberry bushes for sale on Amazon and get ready for tasty summer fruit.
9. Marigolds
Marigolds make great companions for vegetables. Plant them around your veggie patch to repel pests, including rabbits, which don’t appreciate their pungent aroma.
While they don’t harm vegetable plants, the chemicals marigolds give off can hurt hydrangeas. They also have very different growing needs, including full sun, heat, and drier soil than hydrangeas appreciate.
To keep hungry wildlife away from your hydrangeas, spray plants with Liquid Fence, which you can pick up on Amazon. This natural repellent protects plants from greedy grazing deer and rabbits.
10. Garlic
Another plant that can be a useful companion to some and not to others is garlic. Garlic is also allelopathic, which can make it useful for deterring pests from many vegetables. But those same compounds will harm and stunt the growth of hydrangeas.
Also, garlic produces the best, largest bulbs when grown in full sun. Instead of planting near hydrangeas, grow it alongside good garlic companion plants like tomatoes, carrots, brassicas, and herbs.
If you to mix edible plants with your hydrangeas, tuck some spring greens and lettuces, which you can buy from seed on Amazon, under your shrubs for a tasty salad garden anywhere in the landscape.
This article features products available from third party vendors on the Gardening Know How Shop. Keep in mind that our plant inventory is limited—so if you’re thinking of purchasing, don’t wait!
