Choosing plants for your garden is often a little more difficult than simply picking the ones that you adore.
That’s certainly part of it, but there are plants that you should never group together.
Similarly, there are some that work amazingly well together, not only decoratively, sometimes even benefitting the health of each other and of your overall garden.
But how do you know what plants play nicely together, and what plants will try to strangle their neighbors? It can be trial and error to an extent, but it’s more about knowledge, and pooling your knowledge with other gardeners.
Let’s take a look at what plants you should consider grouping together, and those you should absolutely avoid.
What Is Companion Planting?
Companion planting is the practice of grouping certain plants together to benefit the health of all the plants.
Certain combinations will even protect each other from pests, attract pollinators, and produce better crop yields, and it also has the added benefit of looking fantastic.
When gardeners refer to companion plants, they usually mean a combination of flowers, vegetable or fruit crops, and herbs, but it can also mean different flower combinations to extend the flowering season.
Companion planting can help attract beneficial insects, such as hoverflies, bees, and butterflies, while masking the smell of plants that aphids and other pests are attracted to, so they are spared from being eaten.
One classic example of this is tomatoes and marigolds. Marigolds will mask the scent of tomatoes so that aphids and other pests cannot single them out so easily – and they look fabulous against tomato plants, too.
Attracting pollinators helps benefit many plants, but it can also increase the amount of fruit or veggies you get from your garden.
For example, it’s a good idea to plant a crabapple tree, or ornamental blossom tree in an apple orchard to attract more pollinators, which increases the amount of fruit you will get, as these extra pollinators will also visit the other fruit trees.
Why Should You Do Companion Planting?
Companion planting makes for a much healthier garden, when done right.
That’s not to say that you can’t experiment with different combinations of plants, and play around with new ones, but there are some that you should do, and some that you should absolutely avoid at all costs.
Companion planting not only helps the plants be at their best, extending crop yields and bringing more flowers, but it also extends the flowering season if you do it right.
For example, you can plant different plants that bloom at different times in the same bed, and you will have fantastic color all year round. You might start with winter-flowering crocus and spring-flowering tulips to get through the bare seasons before planting for late spring and summer.
Flowers You Should Plant Together
There are many combinations of flowers to choose from. Here are some of the tried and tested mixes that you should grow at least once to see what the fuss is all about.
Tulips And Fritillaria
Fritillaria and tulips flower around about the same time in spring, so planting them together is a great way of bringing out the beauty of both plants, and filling your beds to the brim.
Fritillaria persica, or the Persian lily looks fantastic against a backdrop of red or purple tulips, as it looks somewhat similar in shape, but the striking pattern on the Fritillaria really brings out the contrast in both plants.
Both will tolerate full sunlight or partial shade, and soil with decent drainage. These plants will thrive in USDA zones 4 through to 8.
As tulips are so varied in their looks from cultivar to cultivar, there are literally endless combinations when you plant them with other spring flowers.
To extend the flowering season, plant something that will unfurl just before the tulips start to fade.
Roses And Geraniums
There’s no doubt that roses are beautiful, but they often fall victim to pests, especially if you go for fragrant varieties. And why wouldn’t you want to enjoy their unique perfume?
A tried and tested combination is roses and geraniums. Geraniums give off a lovely fragrance which helps mask the smell of the roses from pests.
Not only that, but geraniums provide a lot of color around the base of roses, which can often look bare and unloved, especially if you go for a standard tea rose, which has a long, thick stem and not much near the soil level.
It also helps that the geranium flowers and leaves provide a gorgeous contrast to the roses, and they like similar conditions.
Geraniums and roses both love a sunny position and well-draining soil, although it’s important to note that some geraniums like the soil to be on the dry side.
What you can do, in this case, is to plant them a little further apart, and have the geraniums at the absolute front of a bed next to paving. When you water the rose, most of it won’t go on the geranium.
Or, you can keep the geraniums in pots at the base of the rose.
Thyme And Roses
Another strong and beautiful combination is planting thyme next to roses. The small and sweet flowers of thyme offset well against the large, more structured blooms of the rose.
Thyme also helps to mask the scent of the rose from pests, and drives away blackfly, which is a particular problem with roses.
Clematis And Jasmine
If you have a large trellis that is begging out for life and color, clematis and jasmine is a great combination, as long as you set them far enough apart to give them both room.
They like similar conditions, as clematis and jasmine are both climbers, and love sun on their flowers and leaves, but prefer the base of the plants to be in shade. If that sounds tricky, you can plant smaller plants in front of them to give them the shade they need.
Echinacea and Rudbeckia
Also known as coneflowers and black-eyed Susans, this combination is perfect for attracting pollinators, providing seas of color in a border, and doing so without needing any attention from you.
Both plants can bloom from late spring well into fall if the weather allows, giving pollinators an extended period where there is plenty of nectar for them.
These plants will tolerate dry conditions, and full sunlight, or dappled shade in the afternoon.
They both need well-draining soil in order to thrive, and while coneflowers will need replanting if you get severe frosts in winter, rudbeckia will die back to the ground and re-emerge the following spring.
Astilbes And Hostas
For parts of the garden where the sun just doesn’t reach, you can’t go wrong with a combination of astilbes and hostas. Both of these plants love damp soil, and shady conditions.
Astilbe produces fantastic flowers in shades of red, white, pink, and purple, brightening up any dark area, and hostas produce huge and beautiful leaves, with lily-like flowers that tower above them.
They both thrive in conditions that sun-loving plants will die in, so there’s no reason to keep a dark area of your garden bare.
It’s worth noting that hostas are particularly vulnerable to slugs, snails, and caterpillars, and one method of dealing with this is to use a solution of garlic and water, and spray it on the plant to stop the pests from munching on the leaves.
Delphiniums And Foxgloves
Another great combination is delphiniums and foxgloves. They are both tall plants with fantastic flowers, and while delphiniums won’t flower for more than a few weeks at a time, foxgloves will flower for longer, providing pollinators with more food.
Both delphiniums and foxgloves come in a range of colors, and if you have a certain color scheme in mind, you can plant complimentary shades to show these plants off.
Irises And Phlox
Irises and phlox both provide lots of color and height into borders, but while irises only bloom in late spring, phlox will bloom just after irises finish, and carry on well into fall if the weather allows.
Both plants will tolerate some form of shade, but do better in at least bright light. Phlox will also tolerate quite a lot of moisture just as irises do, and both attract bees, butterflies, and hummingbirds (see also Flowers That Are Magnets For Pollinators).
Both are perennial plants, so you don’t have to worry about replacing them each year, and they are really easy to take care of, largely doing that themselves.
Plant Combinations You Should Avoid
One thing that might seem obvious but is still worth mentioning is that you should avoid mixing plants that have different watering requirements. Growing thirsty plants against very drought-resistant plants is a bad idea.
For example, putting succulents and irises together would result in the death of both plants, as succulents like very little water, and irises love water.
You can get away with plants that like different light conditions to an extent, for example, planting small plants next to the base of plants that like their roots to be in shade.
Otherwise, avoid planting very tall plants in front of short plants that like a lot of sunlight, as this will stop the shorter plants from growing properly.
One thing to remember is that some plants have evolved to be complete thugs to their neighbors. It’s an evolutionary trait that has meant their survival, and they’re not about to stop now.
Some climbers, for example, if they aren’t given the right space, or they are allowed to grow into other plants, will wreak havoc. Those in the morning glory family, for example.
You should also make sure to steer clear of anything that’s classed as invasive in your area, otherwise you may do more harm than good.
Even plants with long taproots should be avoided in beds. For example, never plant mint in the ground. It will pop up absolutely everywhere thanks to its long taproot, and really, you can grow it in a pot with no issues.
Just make sure that the roots don’t climb out of the drainage holes and make a bid for freedom through the cracks in your patio, because they can, and they will!
If you regularly plant crops in raised beds, you need to rotate the type of crops you plant every year, otherwise you invite disease and pests.
Plants With Allelopathic Properties:
Another thing to consider is that some plants are thought to have allelopathic properties. This is essentially where plants release chemicals to stop their neighbors from growing.
Now, there’s not a lot of evidence in this field, but there are quite a few combinations that seem to do harm, and many gardeners warn each other against planting them together. Here’s a few of them:
- Avoid brassicas and strawberries
- Avoid garlic and onions and beans
- Avoid cucumbers, tomatoes, and potatoes
Flowers You Should Consider Planting Near Fruit And Vegetable Plants
Companion planting mainly refers to planting flowers near crop plants, not only to protect their scent from predators but also to attract pollinators and beneficial insects, and to increase the amount of fruit and vegetables produced.
Marigolds And Tomatoes
Tomatoes and marigolds are one of the most well-known companion plant combinations, and there’s a reason for this!
French marigolds from the Tagetes genus help repel whitefly and other pests thanks to their strong fragrance.
This is really helpful especially if you’re growing tomatoes in a greenhouse, as you will notice that you get lots of pests in the closed environment, more than you might think.
Another combination worth trying with tomatoes is certain types of basil. Some people grow basil in the same pot as tomatoes (see also Growing Basil Indoors), and it’s said that the tomato plants absorb the flavor of the basil.
Borage And Strawberries
Borage plants are a staple of any vegetable garden. They are beautiful plants with starry flowers (which are edible in small amounts, and taste like cucumber).
These flowers attract many pollinators and serve to help the yield of crops. Not only that, but borage is thought to improve the flavor of the strawberries.
Calendula And Zucchini
One of the best pollinator-attracting flowers is calendula. If you’ve grown zucchini before, you’ll know that sometimes pollinators struggle to find the flowers in dull weather, which means a lower yield of zucchinis to harvest.
One of the ways you can improve this is to plant calendula with the zucchini plants, as the pollinators will land on the calendula, and get close enough to notice the zucchini flowers, too.
It also helps that the flowers of zucchini and calendula look fantastic together.
Companion planting is a surefire way of bolstering the health of your garden, not only by bringing the beauty out of the species you plant together, but also in increasing crop yield, flowers, bringing in beneficial insects, and deterring pests from vulnerable plants.
Just make sure that you choose plants that like similar conditions to make it easier on yourself.
It’s also a good way of filling your garden with color if you don’t know where to start as a beginner gardener, while preventing pest infestations that you might not recognize or know how to combat.