Sunflowers (Helianthus spp.) are some of the most recognizable flowers in the world. Many people grow sunflowers for their appearance or to harvest the seeds. Sunflowers are also a popular cover crop that prevents erosion when garden beds or fields would otherwise be empty.
Whether you grow sunflowers alone or alongside other plants, your garden could experience a host of unexpected benefits. In this article, I’ll share the best (and worst) companion plants for sunflowers and how to incorporate them into your own garden.
Understanding Companion Planting
Companion planting is all about growing different plant species that benefit each other. Sometimes you’ll stumble across a combination that benefits all of the plants involved — e.g., the Three Sisters method. But there are also times when only one plant really benefits from the relationship.
Companion planting is a human concept. However, these types of beneficial relationships happen all of the time in nature. One of the simplest examples would be a vine climbing up a sturdy tree trunk to access sunlight.
For the average home gardener, companion planting is both efficient and sustainable. It’s a great way to make the most of your outdoor space while using as few supplies (including chemical products) as possible.
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Reasons To Companion Plant with Sunflowers
When I was a kid, I filled my pockets with dried sunflower seeds with the hope of planting them around the garden and surprising my parents. While I was caught almost immediately (I highly doubt the seeds were viable anyway), the garden may have benefited if I was successful.
While many of these benefits are possible with any type of companion planting, some are unique to sunflowers:
Better Soil Quality: When grown as a cover crop, sunflowers don’t just maintain the existing soil quality. Through complex relationships with soil-borne microbes, sunflowers can actually improve the soil’s texture and the availability of key nutrients.
Pest Control: Aphids are highly attracted to sunflowers. If grown near more desirable crops — i.e., fruits, herbs, and vegetables — any aphids in the area are likely to choose the sunflowers over the rest of your plants.
Weed Suppression: Another benefit of cover crops is their ability to suppress weed growth during the off-season. Since sunflowers have longer growing seasons than many edible crops, you can utilize them to keep your garden weed-free most of the year.
Wildlife Diversity: Most flowering plants attract a number of pollinating species when in bloom. This can be extremely beneficial if you’re growing crops that require cross-pollination for fruit production.
When it comes to sunflowers in particular, I find that the wildlife benefits are twofold. In addition to drawing in pollinators, the large seed heads also attract foraging birds during the later part of the year.
(If you have no other plans for the seeds, I strongly recommend leaving your sunflowers intact until they are picked clean. The seeds are a wonderful source of food for winter birds!)
Wind and Sun Protection: Tall plants can provide much-needed shelter from things like strong winds and intense sunlight when grown next to shorter crops. This strategy tends to be more attractive and easier to set up than a shade net or similar solution.
Structural Support: Tall, sturdy plants may also be utilized by climbing crops in place of the trellis or bamboo poles. Using living plants as garden supports is a great way to maximize the available growing space.
Best Companion Plants for Sunflowers
Many of the best companion plants for sunflowers are edible crops but there are also some great ornamentals worth growing as well. Take a few minutes to read through my recommendations below and learn more about how sunflowers can benefit the other plants in your garden.
Vegetables and Herbs
Sweet Corn: Though relatively easy to grow, sweet corn may fall victim to strong winds when grown alone. Planting sunflowers among your corn stalks creates a natural windbreak and shelters the crop from harsh weather.
In fact, there’s a small farm near me that grows sunflowers in a border around their cornfield. I imagine they do so for this exact reason! It also doesn’t hurt that sunflowers are generally more attractive than corn.
Corn and sunflowers are both tall plants that thrive in the same growing conditions. Sunflowers grow well with the vast majority of corn’s well-known companion plants. However, there are a few exceptions — e.g., pole beans — which I cover at the end of this article.
Lettuce: Did you know that lettuce and sunflowers belong to the same plant family? They also make great garden companions.
One of the trickiest things about raising homegrown lettuce is its tendency to bolt (or prematurely flower) when exposed to high heat. Sowing sunflowers near your lettuce plants is a clever way to ensure adequate shade in the summer months.
Zucchini & Summer Squash: Varieties of summer squash — zucchini being the most popular — also prefer moderate shade when the weather gets hot. Since these plants tend to sprawl along the soil rather than needing a ton of vertical space, you can easily grow sunflowers alongside summer squash for some extra shade.
Sunflowers may also increase pollinator activity around your squash plants, which will have a direct impact on the size of your final harvest.
Melons: The ideal growing conditions for most melons are almost identical to those of summer squash. You’ll have no trouble planting melons next to a patch of sunflowers.
Pest damage is one of the biggest obstacles when growing melons at home and sunflowers naturally deter aphids from crops. The large, yellow flowers also draw in a variety of bird species, many of which will feed on insects plaguing the melon vines.
Tomatoes: I’m always surprised by how few home gardeners I know plant tomatoes and sunflowers together. This is because — when done correctly — sunflowers are one of the best companions for maximizing a tomato harvest.
As I mentioned above, sunflowers distract aphids that would otherwise feed on your tomato plants. But the greatest benefit to growing sunflowers and tomatoes in the same garden is that the combination attracts a huge variety of pollinators.
Both tomatoes and sunflowers like plenty of sun, so take this into account when planning your garden bed. I like to plant my tomatoes closest to the sun since they tend to remain much shorter than the sunflowers.
Cucumber: Cucumbers are very closely related to melons and squash. But I still want to highlight the benefits of growing them along with sunflowers.
You can use sunflowers as natural supports for your cucumber plants. Just be sure to select varieties of each that are well suited to the job — i.e., you don’t want to grow extra-large cucumbers on dwarf sunflowers!
According to SFGate, you’ll see the best results by planting your cucumbers when the sunflowers are at least 12 inches tall. The exact timing will vary based on your local climate.
Peas: Another group of vegetables that will happily climb up nearby sunflowers is the peas. Whether you prefer sweet peas or a different variety, something all peas have in common is a love of cool growing conditions. The sunflowers will also help shade your pea plants from the sun.
As legumes, pea plants are skilled nitrogen fixers. This means that they can take nitrogen molecules from the air and transfer them to the soil. Sunflowers are big and hungry and will make quick work of that extra nitrogen.
Basil: While most culinary herbs grow best in full sun, basil is at risk of bolting when temperatures become too hot. For this reason, I like to utilize taller plants for shade.
It’s already very common to grow basil and tomatoes together, so I encourage you to try planting all three in your garden this year. Just be ready for a potential bumper crop — I hope you like marinara and Caprese!
Nasturtium: Nasturtium flowers look great growing alongside sunflowers but won’t compete for resources. These flowers remain low to the ground and enjoy the cool shade provided by a row of taller plants.
For maximum benefits, plant both nasturtium and sunflowers near your vegetable garden. Like sunflowers, nasturtiums act as a ‘trap crop’ that deters aphids and other pests that would otherwise target edible plants.
Lupine: Lupine shares much in common with the sunflowers in terms of growing requirements. The flowers attract a range of pollinators that are also likely to visit the sunflowers.
Lupine is a type of legume, so these plants will introduce nitrogen into the soil. This nitrogen can directly feed your sunflowers and any other plants growing nearby.
Wildflowers: If you have no particular use for the garden space around your sunflowers, I highly suggest planting some native wildflowers! These blooms will bring color to the landscape and provide a valuable food source for local pollinators.
Some brief research should reveal the best native flower species for your climate and local wildlife.
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Bad Companion Plants for Sunflowers
Despite their many potential benefits, sunflowers aren’t always good garden companions. Sunflowers actually have allelopathic properties, which means that they release chemicals that suppress competing plant growth.
Allelopathic chemicals can impede almost any plant seedlings from growing properly. However, there are a couple of common garden vegetables that are especially sensitive to sunflowers.
Pole Beans: Climbing pole beans seem like swell partners for tall sunflowers but past research shows that the two plants may not mix. This is likely due to the sunflowers’ allelopathic properties.
Potatoes: Unfortunately, I don’t recommend planting potatoes anywhere near your sunflowers. An article from Homes & Gardens claims that growing the plants too close to each other may lead to stunted growth in the potato tubers. There’s also research indicating that sunflowers and potatoes may transfer the disease verticillium wilt back and forth.