Guide to Growing Fennel, Sweet Fennel, and Finocchio

How to Grow Foeniculum Plants

Welcome to the Gardener's HQ Guide on How to Grow Fennel

Fennel is a favourite plant of many cooks.

Although it is a hardy perennial it is usually grown by gardeners as a hardy annual.

It has leaves of a feathery nature and umbrella clusters of very small yellow flowers; these are carried on 10 cm long stalks.

This page is a general growing guide for members of the Foeniculum genus. Go here for specific advice on Growing Fennel in your Garden.

The scientific name for Fennel is Foeniculum vulgare.

Foeniculum vulgare
Foeniculum vulgare – Fennel by John Tann; Creative Commons.

How to Grow Fennel Plants
Florence Fennel by Quinn.Anya; creative Commons.

Foeniculum Growing and Care Guide

Common Names: Fennel, Sweet Fennel, Florence Fennel, Finocchio.
Life Cycle: Hardy perennial usually grown as a hardy annual by gardeners.
Height: 36 to 100 inches (90 to 250 cm).
Native: Mediterranean.

Growing Region: Zones 3 to 10.
Flowers: Late summer and autumn.
Flower Details: Yellow. 20 to 50 tiny flowers on Umbels.
Foliage: Feathery, thread-like. Aromatic.

Sow Outside: 1/8 inch. Before last frost. Spacing 18 to 20 inches (45 to 50 cm).
Sow Inside: Use peat pots. Germination time: ten days to two weeks in the dark. Cool weather; Temperature 65°F (18°C). Four or five weeks before expected last frost. Transplant outdoors following the last frost.

Requirements: Full sunlight for best results, or light shade. Good drainage. Soil pH 6 to 8. Dry soils. Deadhead. In autumn cut back the stems. Propagate: dividing in spring.
Family: Apiaceae.
Miscellaneous: Do not grow close to Dill as the species cross-pollinate. Allow the flower heads to form before harvesting leaves for culinary use. Fruits have an aniseed flavour and can be harvested for culinary use in the autumn; once collected dry them and store in a Tupperware container or similar; over time the seeds will turn from brown to grey. Bulbs of Florence fennel can be used both raw and cooked; they are usually harvested in their second year, but if growing as an annual they will be ready after about three or four months, harvest before flowering for best results.

How to Grow Fennel and other Foeniculum Plants

This section will tell you all that you need to know about how to grow Fennel plants successfully. First off, the Fennel seeds should be planted outdoors at the beginning of spring before the last frost has occurred.

For best results Fennel should be grown in sunny part of the garden even though they are tolerant of light shade.

Fennel and other Foeniculum should be grown in a soil that has a pH of 6 to 8 and good drainage. You may prefer to start growing fennel indoors, to plant outside in the spring or autumn. If so grow the fennel in a peat pot, but do not expect all the plants to survive.

Caring for and Harvesting Fennel in the Garden

Fennel is grown for its leaves, these can be harvested as soon as the plant has flowered. You will find that the fennel (Foeniculum) plant produces more leaves if you remove the flowers after they have bloomed.

It is important not to grow Dill in the same area as Fennel, as the Dill species is closely related and able to cross pollinate! Harvest seeds in the autumn and store in a Tupperware or similar container.

Common Questions

How many members does the Foeniculum genus have?

The Foeniculum genus is quite small, it consists of only two species.

Do members of Foeniculum make a good garden or landscaping plant?

Yes, plants in the Foeniculum genus, such as fennel, can be excellent for gardens and landscaping due to their attractive feathery leaves and yellow flowers.

Which Foeniculum species are most frequently grown by gardeners?

The most commonly grown species of the Foeniculum genus is Foeniculum vulgare, also known as common fennel.

Are members of the Foeniculum plant genus fragrant?

Yes, plants in the Foeniculum genus are fragrant. They release a pleasant, anise-like aroma, especially when their leaves or seeds are crushed.

What is the perfect location to grow Foeniculum?

Foeniculum prefers a location with full sun exposure and well-drained soil. They are tolerant to a wide range of soil types and pH levels.

Is Foeniculum invasive in the USA, if so in which states?

Currently, Foeniculum vulgare, or fennel, is considered invasive in California and Oregon due to its fast-growing nature and ability to out-compete native plants.

How do I remove Foeniculum plants from my garden?

To remove Foeniculum from your garden, pull up the entire plant including the roots. This should be done before the plant sets seed to prevent further spread.


The Foeniculum genus is a small group of flowering plants in the carrot family. Notable for its feathery leaves and yellow flowers, the most commonly grown species is Foeniculum vulgare, or common fennel. This genus is often grown for its aesthetic appeal in landscaping, its pleasant aroma, and its culinary use.

Foeniculum is typically grown in a location with full sun exposure and well-drained soil. It can tolerate a wide range of soil types and pH levels, making it a versatile addition to many gardens. The ideal time to plant Foeniculum is during the spring or fall. Regular watering and removal of spent flowers can encourage healthier growth and prevent the plant from becoming invasive in certain areas.

I hope that you enjoyed this guide on how to grow Foeniculum plants. You may also enjoy the following Gardener's HQ Apiaceae growing guides: How to grow Cumin and Ammi plants.