How Far From Other Plants To Plant Fennel?

The tall green Fennel plant, Foeniculum vulgare, is renowned for its rich licorice flavor, green stems, and bulbous center. Suppose you want to add fennel to your garden. How far should you plant it from other garden varieties? We’ve researched this question and have fantastic answers to share!

It is best to plant fennel plants at a distance of 12 to 18 inches apart. For rows, keep them 2 to 3 feet apart. Fennel plants need ample space for development, pollination, and propagation. 

Are you interested in learning about fennel plants and how to grow these herbs? Or, if you could plant fennel next to flowers? We’ve researched these topics and have gathered quality research results to share with you!

Fennel growing in a vegetable gardenHow Far From Other Plants To Plant Fennel?

How Far From Other Plants To Plant Fennel?

Determining how far apart to plant your fennel plants will depend on a few factors. Such as how many fennel plants are you planning to grow this season? Is it possible to dedicate a portion of your garden solely to growing fennel?

These questions are essential because fennel plants will prevent other varieties of herbs and vegetables from growing or cause them to bolt early in the growing season if planted too close. 

Suppose your garden is already stocked with reliable perennials, and you need room for your favorite annual varieties. If your yard is large enough, you could plant a couple of fennel plants into the landscape to prevent them from overruling your garden. 

How To Plant Several Rows Of Fennel Plants?

The best method to plant several rows of fennel is to plant the seedlings or plants 12 to 15 inches apart. This provides ample room for the plant’s foliage and root system to expand.

Then, ensure your rows are 2 to 3 feet apart at least. Don't try to crowd the rows or plant the fennel seedlings closer together. Overcrowding will inhibit growth, so avoid it when possible. 

Can You Plant Fennel Next To Flowers?

Please note that The Farmer’s Almanac advises against planting fennel plants with flowers, herbs, and other vegetables. This is because fennel is a sizeable plant that requires a lot of space to develop.

Also, it does not make a quality companion with different varieties of flowers, herbs, or vegetables for this reason.

If you are short on space for your garden and must plant the fennel plants next to your favorite rose bush, the fennel plant will help protect the rose bush from aphids. 

Also, if you add a fennel plant or two to your butterfly garden, plant the fennel at the edge of the garden. These plants will draw insects and pollinators such as native bees, ladybugs, and butterflies.

Do you have roses in your garden? Are you curious about which plants will make the best companions? Click here to read 25 Fabulous Companion Plants for Roses

Genuine and fresh raw fennel on a rustic background

Generally, it is not wise to plant other varieties of plants with fennel because the root system will rapidly absorb nutrients and leave the other plants undernourished. Plant the fennel separate from your garden or flower beds for the best results. 

Do not plant fennel next to cilantro or dill because there is a high chance the plant species will cross-pollinate. 

Consider raising the fennel in a small garden solely for your fennel plants to ensure there is plenty of space for the fennels’ expansive root system.

Otherwise, if you are only planting a couple of fennel plants, add those to your landscape to keep them separated from other plants. 

Lush fennel growing in an ordered vegetable patch

Is Fennel Annual Or Perennial?

Excellent question! Whether the fennel plant is annual or perennial, you can determine this based on the zone where the flowers were planted.

For example, if you plant fennel seeds in Zones 4 through 9, the plant will return the following growing season as a short-lived perennial. 

Suppose you plant the seeds in a colder climate in Zones 2 through 3. The fennel plants will grow annually and will not return organically the following growing season. 

How To Find Your Zone?

For the best results, use the link below to determine your zone and how those growing conditions pertain to your garden.

Click here to use the USDA Plant Hardiness Zone Map.

How Does Fennel Reproduce? 

The fennel will quickly grow from reseeding or sprout from the bulb. Gardeners have reported that planting the bulb/stalk in a pot will produce a healthy plant within a month or so. 

Otherwise, saving the seeds from one year to the next is an excellent option for ensuring your garden will always have fennel plants each growing season.

Are you interested in vertical gardening and wondering how to level up your green wall? Click here to read 23 Vertical Gardening Tips That Will Take Your Green Wall To The Next Level

Do Butterflies Like Fennel?

Yes! According to the Univerisity of Oklahoma, fennel plants are excellent for butterfly gardens and will help sustain the butterfly populations throughout the species’ lifespan.

The Anise Swallowtail and Black Swallowtail butterflies have a strong attraction to fennel plants simply because the branch-like stems are great for the larval stage.

Fun fact, the fennel's stems will give the larval a sheltered place to develop, and the larvae will not harm the plant’s overall health.  

Anise Swallowtail Butterfly (Papilio Zelicaon) Pollinating in a Flowerbed of Orange, Yellow, and Purple Flowers Blossoming in Springtime

Click here to view the Sow Right Fennel seeds at Amazon. 

Eastern black swallowtail butterfly, Papilio polyxenes asterius

How Big Do Fennel Plants Get?

According to the University of Wisconsin, fennel plants will grow up to 6 feet tall provided the plant has adequate nutrition, clean water, full sunlight, and room for the roots to expand without inhibiting other plants.  

Most gardeners will harvest the plant when it’s about a foot or less. Of course, how long to wait before harvesting your fennel bulbs is entirely up to your personal preferences.

How To Mulch Around Fennel Plants?

The Farmer’s Almanac advises to pull weeds before mulching. Without removing the weeds before adding the mulch. Those weeds will grow through the mulch and consume nutrients from the soil that the fennel plants could absorb instead.

A word of caution: Don’t use more mulch than necessary or have it uneven with areas of over 1-inch in any area. Over-mulching will diminish the oxygen supply to the fennel plants’ root systems.

Also, over-mulching will encourage fungi mats to flourish. Those fungi mats will repel the water you want to conserve for your flowers, herbs, and veggies’ root systems. 

Can You Grow Fennel In Pots?

Yes. You could grow fennel in pots if the growing containers are large enough for the plant’s expansive roots. 


Click here to view Vivosun plant containers at Amazon. 

Does Fennel Like Sun Or Shade?

Fennel plants need full sun and hot conditions to yield fruitful results. In short, “full sun” means the plant needs at least 6 hours a day of direct unfiltered sunlight to grow and produce tasty fennel bulbs.

Are you wondering what the definition “full sun” means when shopping for plants at your local greenhouse? Click here to read What Does “Full Sun” Mean In Gardening?

Can Fennel Survive A Frost?

The hardy fennel plants will tolerate a light frost in the early fall without sustaining any damage. However, the first hard frost will cause the plants’ foliage to die.

Depending on your zone, the fennel plant will return as a perennial in the springtime. 

In Closing

All of us at Garden Tabs appreciate you taking the time to read our article, and we hope you have found it helpful.

Today, we discussed how to plant, care for, and mulch fennel plants. You want to ensure they have the best conditions to produce healthy fennel bulbs and have a bountiful return after a long winter when spring returns!

Please be sure to check out some of our other posts before you go!

18 Herbs That Like Full Sun For Your Kitchen Windowsill

How Far Apart To Plant Incompatible Plants?

Does Rain Wash Away Pesticides?

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