Have you ever wondered what you can plant next to your rosemary? Not every herb or vegetable is a good rosemary companion. Choose a bad companion and this might cost you your dear rosemary.
The best rosemary plant companions are french beans, plants from the brassica family, carrots, onions, and sage. The worst rosemary companion plants are cucumber, watermelon, and those that require lots of water. A rosemary companion plant should only require moderate water and 6 to 8 hours of sunlight.
To identify if your rosemary’s companions are good or not, let us find out what companion planting is.
What is Companion Planting?
Companion planting is the practice of growing two different plants in the same container. The distance between one plant to another must be approximately 6 to 12 inches apart.
There are things that you need to consider when doing companion planting. This can only be done if the plants have the same light, water, and soil requirements. Let us find out what benefits and possible challenges you can meet when practicing companion planting.
Benefits of Companion Planting
Growing plants together is helpful for the following reasons:
- Repels pests and insects by emitting scents that mask insect desirable plants’ odor.
- Creates a refuge for beneficial bugs and other pollinators that will help produce seed distribution and reproduction.
- Provide good soil nutrients for plants to grow.
- Increases growth and high yield of harvest.
Repels Pest Insects
One important benefit of companion planting is repelling pests. The choice of proper plant combinations can create the plants’ natural ability to invite, despise, or put off insects.
For example, rosemary is known to be a good companion for cabbage, broccoli, and other plants in the brassica family. Rosemary’s fragrance repels insects such as cabbage flies, root maggots, and other flying pests or insects that will kill your plants in the garden.
Not all insects are enemies in the garden. Many of them can help plants grow by eating other harmful pests.
For instance, growing plants like rosemary and dill invite beneficial pests like bees and other pest-eating insects. They control the multiplication of caterpillars, beetles, and aphids that are slowly killing your plants. Moreover, bees suck the nectar, and the rosemary flower gets pollinated where a new plant will grow. Dill may be a good companion to other plants, but it is not a good companion to rosemary because dill cannot survive in hot weather.
Plants grow by getting nutrients from the soil. However, there are plants that interact with beneficial bacteria that can improve the nutrient level.
Legume plants like beans, peas, and clover, have a beneficial relationship with nitrogen-fixing Rhizobium bacteria. According to an excerpt from Rodale’s Successful Organic Gardening Series, these Rhizobium bacteria penetrate the roots absorbing 20% of sugar the plants produce.
The sugar is converted into energy which will be used by the bacteria to capture useful atmospheric nitrogen gas and convert it into a new form of nitrogen compounds that can be used by your other plants. In other words, these bacteria help the roots to decompose faster and produce nitrogen that will help the growth of nearby companions.
Increases Growth and Harvest
Companion planting can increase the growth of plants and lead to higher yields.
For example, the scent of rosemary drives away insects that might damage your cabbage, lettuce, broccoli, carrots, and onions. This is just one of the many examples of companion planting benefits.
Challenges in Companion Planting
Where benefits are enjoyed by gardeners, there are also challenges that must be taken into consideration in companion planting.
- Companion plants may affect growth and reduce their economic yield.
- There is a possible outbreak of secondary pests.
Decreases Growth and Harvest
When companion planting is done wrong, it can reduce the growth and health of the plants involved.
For example, if rosemary is planted close to cucumber, it might die (due to the different water requirements). This will not only attract insects that feed on the rotten plant but also they might attack the cucumber.
Secondary Pests Outbreak
Another example of problems of bad companion planting is the possibility of a pest outbreak.
This means that when one of the plants drives away the predators, the number of prey will increase because the area has become a safer place for them to multiply. It will demand additional pest control management.
For example, rosemary repels spiders. Spiders hate the aroma produced by rosemary. That is why you can never find any spider in your rosemary plant. Aphids are attracted to rosemary since no insect predators will eat the aphids, such as spiders. Then, aphids will have the opportunity to multiply.
Aphids in small numbers are not very harmful to your rosemary. When they multiply, they can produce honeydew which causes the growth of mold and mildew on the leaves. Therefore the best way is to manually remove the aphids when they are still small in number. When they multiply rapidly, you may release ladybugs in the bush of your rosemary and let these tiny red beetles do the job of eliminating the aphids.
Plant Companion Chart
There are a lot of possible plant companions in the chart in which starting is always a challenge. Rosemary plants are good companions to others, but we must also know which plants are suitable companions for rosemary.
Let us check the companion planting chart below to see if the plants you have in the garden are friendly or not to your rosemary.
|HERBS||Good Companion Plants||Bad Companion Plants|
|Rosemary||French Beans, Brassica Family, Carrot, Onions, Sage, Potatoes, Beetroot, Radish||Cucumber, Watermelon, Aubergines, Sweet Corn, Celery, Courgettes, Marrows, Pumpkin, Winter Squash, Tomatoes|
|Basil||Asparagus, Marigold, Pepper, Tomato||Beans, Brassica Family, Cucumber, Rue|
|Catnip||Beans, Broccoli, Cucumber, Pepper, Potato, squash|
|Chamomile||Beans, Brassica Family, Garlic Onion|
|Chives||Carrot, Celery, Cucumber, Lettuce, Roses, Tomato||Beans, Peas|
|Cilantro||Caraway, Celery, Eggplant, Parsley, Peas, Potato, Tomato||Fennel|
|Dill||Brassica Family, Cucumber, Lettuce||Carrot, Fennel, Tomato|
|Fennel||None||Beans, Caraway, Cilantro, Dill, Pepper, Tomato, Wormwood|
|Mint||Brassica Family, Peas, Squash|
|Oregano||Beans, Cucumber, squash|
|Parsley||Asparagus, Carrot, Cilantro, Corn, Pepper, Roses, Tomato|
|Sage||Brassica Family, Carrot, oregano, rosemary, strawberry, tomato||Chives, Cucumber|
|Thyme||Brassica Family, Eggplant, Potato, Strawberry, Tomato||Cucumber|
Best and Worst Plant Companions of Rosemary
It is important to know the best and worst companion plants of rosemary. Failure to do so will cost you one of the two plants.
Let us find out more.
Best Rosemary Companions
- French Beans
- Brassica family
These plant companions require similar watering, sunlight exposure, soil fertility, and soil drainage. Moreover, these companions also benefit from the aroma that rosemary has. Its solid spicy scent drives away pests like cabbage moths and flies, which destroy these vegetables’ yield.
Worst Rosemary Companions
- Sweet Corn
- Winter Squash
- Broad Beans
- Runner Beans
Many said that Cucumber hates aromatic plants. However, there is not much scientific evidence that can prove how the aroma of rosemary adversely affects cucumbers. A more practical reason that makes them not good companions are the cultural practices that they need. Although rosemary and cucumber can grow in full sun under light shading, the same temperature, loamy, and slightly acidic soil, they differ in water requirements.
Cucumbers need a constant water supply to produce high-quality yields. On the other hand, rosemary does not require too much water since it will shorten its lifespan. That is why watermelon, aubergines, sweet corn, celery, courgettes, marrows, pumpkin, winter squash, and tomatoes are not good companions for rosemary because these plants require much water.
Now that we have identified the best and worst plant companions for rosemary, let us determine if these common herbs and plants can be good companions for rosemary.
Rosemary and Other Plants
I get asked quite often if rosemary can be planted with basil, thyme, lavender, or tomato. This is because they are pretty common plants.
Any plants that require the same cultural practices as Rosemary (lighting, drainage, soil type, and water) can grow together. Let us find out if this is the case with the following combination.
Rosemary and Basil
Rosemary and basil are not a good companion plant pair. Despite that, both grow well in full sun; basil needs more water than rosemary. If you plant them together, one will thrive, and the other will die.
Rosemary and Thyme
Thyme and rosemary can grow together in the same planter since both meet the same environment and conditions needed to grow well. From the table above, they also have friends and foes in common. Moreover, rosemary can grow up to 6 feet compared to thyme, which can only grow up to 12 inches. Therefore, it is advisable that when you plant them together, there must be a wider space enough for them to grow well.
Rosemary and Lavender
Rosemary and lavender are great companion plants that can be easily grown in the same pot.
Both are drought-tolerant, and not all can survive during the winter season. You may know some people whose rosemary died when planted together with lavender. This does not mean that they are not good plant companions.
They can grow together, but we can presume that the problem is how the person took care of the plants. It could be the amount of water, less exposure to sunlight, or maybe the type of soil used. When you see that one of them is not growing well, immediately transfer the other and take the necessary steps to revive the plant.
Rosemary and Tomato
It is not beneficial that rosemary and tomato will grow together. Although both can grow at the same temperature, they differ in the amount of water needed for each other. If both are planted in a container, tomatoes will suffer dehydration because the soil in containers quickly heats up, leading to faster evaporation.
Consequently, if you want to put more water in favor of tomato, rosemary will also suffer since too much water can cause its roots to develop moisture, leading to its discoloration of leaves and, worse, its death.
Summary of Rosemary Companion Plants
- Rosemary is an easy-to-grow herb beneficial to garden biodiversity.
- The excellent plant companions of rosemary are cabbage, broccoli, and other plants in the brassica family, french beans, carrot, onions, sage, potatoes, beetroot, and radish because they require a moderate amount of water and much sunlight.
- The worst plant companions of rosemary are cucumber, watermelon, aubergines, sweet corn, celery, courgettes, marrows, pumpkin, winter squash, tomatoes, and those plants that need much water for growing.
- Lavender and thyme are good plant companions to rosemary, while tomato and basil are not.
- The plant companion chart is the best tool to refer to when deciding which plants you want to grow together.
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“Companion Planting and Insect Pest Control” by Parker et al. in CDN INTECH
“Companion Planting Made Easy” by Rodale Press Inc. in Rodale’s Successful Gardening Series
“Companion Planting: Basic Concepts and Resources” by George Kuepper & Mardi Dodson
“Brassica Care: New Farms for New Americans 2010” by NESFP.ORG