Companion planting is a gardening method where different species are grown in close proximity to benefit one another. Think of it as "nature’s matchmaking." By pairing specific plants, you can create a mini-ecosystem that improves plant health, increases yield, and reduces the need for chemicals.
Companion planting techniques work well in both vegetable gardens and annual flower gardens.
Companion Planting in Vegetable Gardens
Key benefits of companion planting for vegetables include:
- Pest control. Certain plants emit scents that repel harmful insects or act as a "trap crop" to lure pests away from your main harvest.
- Natural support. Tall, sturdy plants like corn or sunflowers can act as living trellises for climbing plants like beans or peas.
- Soil health. Some plants, particularly legumes like beans and peas, "fix" nitrogen in the soil, making it available for neighboring plants that need it.
- Space management. You can maximize your garden beds by planting fast-growing crops like radishes between slower-growing ones like tomatoes.
- Shade and mulch. Plants with large leaves like squash provide "living mulch," shading the ground to keep soil cool and suppress weeds.
Famous Examples of Companion Pairings
They just go together, like:
- Tomatoes & Basil. Basil is thought to improve the flavor of tomatoes and repels flies and mosquitoes.
- Carrots & Onions. The scent of onions or leeks helps mask the smell of carrots from the carrot root fly.
- Roses & Garlic. The strong aroma of garlic or chives helps deter aphids, which frequently attack rose buds.
- Cabbage & Dill. Dill attracts beneficial predatory wasps that prey on cabbage loopers.
Plants to Keep Apart
Just as some plants are "best friends," others are "enemies" and can stunt each other's growth if planted too close.
- Onions & Beans. Onions can stunt the growth of beans and peas.
- Tomatoes & Corn. Both are susceptible to the same type of earworm and fruitworm, which can cause a double infestation.
- Potatoes & Tomatoes. They are both prone to early and late blight, so keeping them separate helps prevent the spread of disease.
Dos and Don'ts
If you want to grow a particular plant, there are often desirable companions as well as plants that you'll want to avoid.
| To Grow | Plant These Nearby | Keep These Away |
|---|---|---|
| Peppers | Basil, Onions, Spinach | Fennel, Kohlrabi |
| Zucchini or Squash | Corn, Beans, Dill | Potatoes |
| Broccoli or Kale | Rosemary, Sage, Mint | Strawberries, Tomatoes |
| Potatoes | Beans, Corn, Horseradish | Sunflowers, Tomatoes |
Companion Planting in Annual Flower Gardens
Choosing companion flowers for annuals is all about balancing aesthetics (color and texture) with functionality (pest control and soil health). Since annuals only have one season to shine, you want companions that grow at a similar speed.
Here is a breakdown of the best pairings, depending on what you want to achieve in your garden.
"Power Couple" Pairings
These are classic combinations where one plant physically or chemically benefits the other.
- Zinnias & Cosmos. Both love full sun and heat. Cosmos add airy texture to the bold Zinnia heads.
- Geraniums & Bacopa. Geraniums provide height, while Bacopa trails over the edges as a "spiller."
- Petunias & Sweet Alyssum. Alyssum smells like honey and masks the "leggy" stems of older petunias.
- Sunflowers & Morning Glories. Morning glories can use the sturdy sunflower stalks as a natural trellis.
Best for Pest Protection
If you want your garden to be low-maintenance, use these "defender" annuals to keep bugs away from your showier blooms.
- Marigolds. The "gold standard" of companions. They produce alpha-terthienyl, which helps repel root-knot nematodes and discourages aphids. Plant them with Petunias or Salvia.
- Nasturtiums. These act as a "trap crop." Aphids love them so much they will often congregate on the Nasturtiums and leave your Sweet Peas or Snapdragons alone.
- Calendula. These daisy-like flowers attract beneficial insects like hoverflies, which eat garden pests. They look stunning tucked between Pansies or Violas.
Design-Based Combinations
Professional gardeners often use the "Thriller, Filler, Spiller" method for containers and beds.
- Thrillers: Angelonia, Snapdragon, or Canna Lily for height.
- Fillers: Lantana, Heliotrope, or Begonias for bulk.
- Spillers: Lobelia, Calibrachoa (Million Bells), or Dichondra for drape.
Environment Considerations and Tips for Success
Factors related to the location of your garden will also affect the types of flowers that you plant together.
- Water Requirements. Don't pair drought-tolerant flowers like Portulaca with water-hogs like Impatiens, or one will surely suffer.
- Light Needs. Ensure both plants share the same sun requirements. For example, Coleus and Begonias both love shade and are a perfect match, but neither will do well next to a sun-loving Zinnia.
- Deadhead Buddies. Many annuals stop blooming if they go to seed. Choosing companions that both require deadheading makes your garden chores easier to do all at once.
