5 Best Fennel Companion Plants For Gardens (And 11 To Avoid)

Are you having trouble getting your fennel to thrive in your garden? I struggled with spotting the right partners for this fragrant herb as well.

Based on my experience and extensive research, I’ve discovered that finding the right fennel companion plants is key to cultivating a flourishing patch.

Lettuce, mint, peas, sage, dill, and lemons all grow great next to fennel, but there are a lot of plants to keep fennel away from, such as basil, beans, cucumbers, caraway, cilantro, eggplants, kohlrabi, peppers, potatoes, thyme, and tomatoes.

Fennel can often be detrimental to the development of other plants, so you should put some distance between them. Let’s explore the best, and worst plant buddies for your feisty fennel!

Key Takeaways

  • Dill, lemon, lettuce, mint, peas, and sage are excellent companion plants for fennel, as they enhance its growth and repel pests.
  • Basil, beans, caraway, cilantro, cucumbers, eggplant, kohlrabi, potatoes, and tomatoes should be avoided as companion plants for fennel as they may hinder its growth or attract pests.
  • Choosing the right companion plants for your fennel garden can promote a healthier environment and better yields while maintaining distinct flavors and aromas.

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Understanding Fennel: An Overview

fennel companion planting

As a full-flavored plant, fennel is also an aromatic species, and its role in the garden is often misunderstood.

As part of the Apiaceae family, it contains powerful essential oils that are brimming with numerous vitamins and minerals beneficial to our immune system.

Alongside these health benefits, these garden plants have been historically used for treating conditions such as gout or supporting organs like the kidneys and heart.

Despite its culinary traditions and medicinal uses, fennel tends to get a bad rap when it comes to companion planting—mostly due to some internet rumors.

Yet contrary to its reputation as a poor companion plant, many experienced gardeners have reported successful growth when pairing fennel with select plants such as dill.

There’s more hiding beneath those fragrant fronds than meets the eye! As a drought-tolerant plant packed with nutrients like copper, manganese, vitamins A & K, and rich fiber content, it has definitely earned its place in our gardens.

However, as fascinating this flowering member of the carrot family might be, successfully growing fennel requires understanding certain points about its nature—like being aware of its distinctive allelopathic characteristics which can cause chemical stunts or disrupt other plants’ growth if not properly managed.

Planting and caring for this annual herb extend beyond providing well-drained soil or maintaining proper water levels—it’s all about smart positioning among other plants too!

The Importance of Companion Planting

fennel companion plants

Companion planting provides a garden with its own mini-ecosystem where plants work together in harmony.

It’s a crucial aspect of gardening to understand, especially when growing fennel because companion planting can have big impacts on growth and flavor profile.

Companion planting uses the natural traits of different species to achieve mutual benefits like deterring insects, enhancing growth, and improving soil health.

Certain insects are attracted to fennel due to its strong aroma, which they see as beneficial for their survival.

These include ladybugs, syphid flies, tachinid flies, parasitoid wasps, and hoverflies—all known for effectively managing aphids.

Since fennel is so aromatic and aphids themselves cannot stand the scent of fennel, they’ll keep away from your garden area if you grow this plant.

Moreover, fleas despise the smell that comes off our lovely, fragrant buddy—fennel! This quality makes it an excellent choice for flea repellent around kennels or other areas where dogs may frequent.

So, beyond just considering what grows well side by side with your fennel plant in terms of sunlight needs or water usage; remember also how it can protect other plants from unwanted creatures while attracting those who help us out against pesky bugs!

In addition to these pest-deterrent benefits, choosing good companions for your fennel could improve their overall health and yield too!

Different types of vegetation bring unique advantages, such as supplementing nutrients in the soil or offering shade from harsh sun rays, depending upon their inherent characteristics, forming symbiotic relationships that are indeed worth fostering.

Characteristics Of Fennel

Plant Family
Watering Conditions
Well-draining soil, keep soil consistently moist
Mature Size
Typically 3-8 feet tall and wide
Soil Requirements
Rich, well-draining soil; pH 6.5-8.0
Sunlight Needs
Full sun
Temperature Tolerance
Cool-season herb, sensitive to frost; thrives in USDA zones 4-9
Growth Habit
Perennial herb, often grown as an annual
Flowering Period
Flower Color
Foliage Characteristics
Feathery, aromatic leaves
Propagation Methods
Seeds (direct sowing)
Pruning and Maintenance
Regularly harvest leaves to promote bushiness; remove flower stalks to prolong leaf growth
Common Pests and Diseases
Few pest or disease issues; may encounter aphids or caterpillars
Companion Planting
Dill, tomatoes, onions, and other herbs
Edible Parts
Edible leaves (fresh or dried) and seeds (used as a spice)
Wildlife Attraction
Fennel flowers attract pollinators like bees and butterflies
Generally non-toxic; some people may have allergies or sensitivities
Special Care Instructions
Fennel can be invasive, so consider planting in a contained area; provide consistent water

The Best Fennel Companion Plants

companion plants for fennel

Unfortunately, fennel doesn’t have many growing partners. In fact, fennel is known as a plant you should sometimes avoid, as it can disrupt the healthy growth of other plants.

Despite that, there are a few plants to grow near fennel; read about them in detail below.

1. Dill

Dill is a plant that actually resembles fennel and shares a great friendship with this perennial plant in the garden.

These two might look similar with their feathery leaves, but don’t let that fool you; these are distinct plants, each boasting unique benefits.

Just as fennel attracts beneficial insects, this annual plant also promotes growth and health in fennel by attracting helpful insects like ladybugs, syrphid flies, and parasitoid wasps that keep pest populations under control. However, there’s an intriguing plot twist: dill and fennel can cross-pollinate.

While this creates exciting drama for us gardeners, it could lead to hybrid seeds with less-than-ideal taste!

Luckily, there’s an easy solution: simply harvest your dill before it bolts, and you’ll have the best of both worlds: healthy fennel plants and flavorful dill seeds.

After all, it’s about creating harmony and balance in our gardens!

2. Lettuce

It’s a good idea to plant lettuce and fennel together, as both plants benefit from this partnership. When planted next to lettuce, fennel not only adds beauty to your garden but also serves as a natural deterrent for lettuce bugs.

By planting lettuce next to fennel, you can protect your lettuce’s foliage from harm.

The two plants have compatible growing conditions and can coexist well in the garden. Plus, having lettuce nearby can improve the overall health and yield of both plants.

So if you’re looking for a beneficial companion for your fennel, consider planting some crisp and leafy lettuce alongside it!

3. Mint

Fennel and mint form a great companionship as the two plants complement one another.

When I plant mint alongside my fennel, it not only maximizes the use of space in my garden but also helps deter pests and attract beneficial insects.

Mint has antibacterial properties that promote overall plant health and prevent disease. Plus, since it’s also an aromatic plant, it’s known to repel aphids, which can be harmful to fennel.

If you’re growing fennel, consider adding some mint nearby for a healthy and pest-free garden, but make sure not to plant too much, as mint can be invasive if it’s not controlled properly.

4. Peas

One of the best plant pairs for fennel is peas. Peas not only repel pests that could harm fennel, but they also attract beneficial bugs like ladybugs and hoverflies that can help protect the fennel from pests.

Planting peas and fennel next to one another can improve the overall health and growth of both plants.

Another benefit of planting peas with fennel is their nitrogen-fixing abilities, which enrich the soil and benefit the growth of fennel.

So, consider adding some peas next to your fennel in your garden for a thriving crop!

5. Sage

Fennel is a good companion plant for sage, and the two complement each other nicely. They not only look good side by side but also help keep invasive animal species at bay.

Fennel can sometimes attract unwanted insects and diseases, but having sage nearby can act as a natural deterrent.

So, if you’re growing fennel, consider planting some sage alongside it to reap the benefits of this beneficial pairing.

Bad Companion Plants For Fennel

Basil, beans, caraway, cilantro, coriander, cucumbers, eggplants, kohlrabi, peppers, potatoes, thyme, and tomatoes are all best grown far away from fennel. Here’s why:

1. Basil

Basil is not a good plant to put close to fennel. This aromatic herb can actually hinder the growth and development of fennel plants, but fennel can also negatively affect basil.

Fennel emits substances into the soil that can inhibit the growth of neighboring plants like basil; we call this an allelopathic characteristic.

So, if you want healthy and thriving fennel and basil plants, it’s best to separate the two plants as far as possible.

2. Beans

Beans can grow next to many plants, but fennel isn’t on the list. Beans are also known to have allelopathic characteristics, and the chemicals they release into the soil directly affect your fennel plant’s growth.

If you plant beans near fennel, they may cause it to struggle or even die. Keep beans away from your fennel plants in order to ensure their successful growth and development.

3. Caraway

Do not plant caraway next to this plant either, as it also has allelopathic characteristics that are detrimental to fennel. Fennel grows best far away from caraway, and planting them together will result in a hybrid plant.

The presence of fennel can also negatively affect the development and yield of caraway.

So, if you’re growing fennel in your garden, it’s best to keep it away from caraway to ensure both plants thrive independently.

Fun fact: did you know that caraway is also known as meridian fennel? The two are actually related!

4. Cilantro

Cilantro is not a good plant pairing for fennel. It restricts the growth of both plants and prevents seed production. Planting cilantro and fennel together can disrupt their growth and development.

Due to its allelopathic nature, fennel may adversely affect neighboring plants as well. Additionally, growing cilantro alongside fennel can result in poor-quality hybrid plants.

If you want cilantro in your garden, I recommend you don’t plant it next to fennel.

5. Cucumbers

Keep cucumbers and fennel far away from one another because, just like with many plants before, fennel can inhibit the growth of cucumbers.

It is recommended to keep a distance of at least 2–3 feet between fennel and cucumber plants to avoid any negative effects.

Furthermore, planting fennel near cucumbers can attract pests and diseases that may harm the cucumber plants.

With all of that in mind, keep these two plants separate in the garden for optimal growth and protection of your cucumber plants.

6. Eggplants

Eggplants should also be avoided as companion plants with fennel. They have the potential to inhibit the growth of fennel and can also result in poor-quality hybrid plants when grown together.

This is due to both the fennel’s and the eggplant’s allelopathic nature, as both species release chemicals through their roots that can hinder the growth of the other plant.

So, if you’re planning a garden with fennel, it’s best to keep eggplants at a distance to ensure healthy and thriving plants for both species.

7. Kohlrabi

Kohlrabi is not recommended as a companion plant for fennel. Planting kohlrabi close to fennel can inhibit its growth and yield thanks to fennel’s allelopathic properties, so it’s best to keep them at least 2–3 feet apart.

To ensure the success of both plants, it’s advised to avoid planting kohlrabi and fennel close together.

8. Peppers

Peppers are a fantastic addition to any vegetable garden, but they should be avoided as companions for fennel. Fennel and peppers have different needs when it comes to sunlight, water, and soil conditions.

While fennel prefers full sun and well-drained soil, peppers thrive in partial shade and require consistently moist soil.

Planting them together could lead to competition for resources and stunted growth for both plants.

It’s best to keep these two separate in your garden to ensure the health and success of each plant individually.

9. Potatoes

There’s a short list of plants that aren’t compatible with potatoes, and that list includes fennel.

This is due to the substances that fennel emits into the soil, which can interfere with neighboring plants and affect their yield and quality.

It’s important to keep this in mind when planning your garden layout and choosing fennel companion plants.

10. Thyme

Thyme is a plant that should be avoided when companion planting with fennel. Thyme has allelopathic characteristics, which means it releases chemicals that can inhibit the growth of nearby plants.

When planted near fennel, thyme can disrupt the growth and development of both plants. It’s best to keep these two herbs separate in your garden to ensure their optimal health and productivity.

So, if you’re planning a mixed herb garden, remember to keep thyme away from your fennel!

11. Tomato

These members of the nightshade family should be kept far away from fennel. This is because fennel has allelopathic characteristics, which means it releases chemicals that can inhibit the growth of other plants.

Out of all the plants on this list, tomatoes may be the most sensitive to fennel.

Final Thoughts

While fennel is often considered a challenging plant to companion with, there are several successful pairings that can enhance its growth and repel pests.

Dill, lemon, lettuce, mint, peas, and sage are all great companions for fennel.

On the other hand, it’s best to avoid planting basil, beans, caraway, cilantro, cucumbers, eggplant, kohlrabi, potatoes, and tomatoes near fennel, as they may hinder its growth or attract pests.

With careful planning and consideration of companion plants, the beauty and benefits of growing fennel can be maximized in your garden.

FAQs About Companion Planting Fennel

What should you not plant near fennel?

Avoid planting fennel near most other garden vegetables, especially beans and tomatoes, as it can inhibit their growth due to its allelopathic properties.

Is fennel dangerous for other plants?

Yes, fennel is considered allelopathic, releasing chemicals that hinder the growth of neighboring plants, particularly certain vegetables and herbs.

How far away from other plants should you plant fennel?

Plant fennel at least 2–3 feet away from other plants to minimize its allelopathic effects and prevent competition for resources.

Can I plant fennel next to tomatoes?

It’s not recommended to plant fennel next to tomatoes due to fennel’s allelopathic properties, which can negatively impact tomato growth.

What are the best companion plants for fennel?

Some good companion plants for fennel include dill, chamomile, basil, marigold, and rosemary.

Can I plant fennel next to other vegetables?

Fennel can be planted next to certain vegetables like lettuce, cabbage family crops (such as broccoli or kale), and onions.

However, it should be avoided near beans and tomatoes, as they may inhibit each other’s growth.

How far apart should I space my companion plants from the fennel?

It is generally recommended to space your companion plants about 12-18 inches away from the base of the fennel plant to allow enough room for growth and airflow between them.

Does fennel make a good companion plant for peas?

Yes, fennel makes a good companion plant for peas. The aromatic qualities of fennel can help deter pests that commonly affect peas, such as aphids and greenflies.

Can I plant fennel next to sage?

Yes, planting fennel next to sage is a good choice. Sage is a good companion plant for fennel and can help deter certain pests.