Among the many wonderful herbs available to the gardener, no honest-to-goodness herb garden is truly complete without at least one tall, stately fennel plant. I say that because fennel is not only edible, medicinal and downright gorgeous, but it also attracts hordes of beneficial insects and butterflies to the garden, too. What more could any gardener, cook or herbalist ask for?
Despite its obvious charms, fennel is one of those herbs that even long-time gardeners seem to overlook. Indeed, I am always surprised by gardeners who mistake my fennel for dill. Perhaps it is the fern-like leaves or the umbels of bright yellow flowers – after all, the two are closely related and have a very similar shape and form. But once you have grown fennel in your own garden and tasted its luscious anise-like flavor, you will never mistake it for anything else.
Fennel for the Garden
Cultivated fennel comes in three basic varieties, all of which belong to the vast and diverse Apiaceae, or Parsley Family of plants. A few members of this family include common culinary herbs such as parsley, dill, cilantro/coriander, anise, and fennel. It also encompasses several traditional vegetables like carrots, celery and parsnips.
There are three varieties of cultivated fennel, including:
Sweet Fennel (Foeniculum vulgare dulce)
Bronze Fennel (Foeniculum vulgare dulce var. ‘Rubrum’ or ‘Purperium’)Florence Fennel (Foeniculum vulgare var. azoricum)
All true fennels begin their first growing season as a basal rosette of finely-dissected, fern-like leaves, which quickly grow into thick upright stalks that can reach upwards of 5 feet or more before flowering. Fennel leaves are finely dissected with a swollen stem base that clasps the main stalk in a thin membrane. As the plant matures, new leaves and flowering umbels emerge from within the protection of these papery sheaths. Florence fennel does the same thing, only its leaf stems are thick and bulbous and grow so closely together that they form a nearly solid mass close to the ground.
The tiny, bright yellow flowers of fennel are born singly atop long, thin pedicels (tiny stems) that are bunched tightly together in clusters of 20-50 to form the classic flat-topped umbels so closely identified with members of the Parsley Family. Once the flowers begin to fade elongated and slightly ribbed fruits emerge. As the fruits dry they turn varying shades of brown, eventually splitting into two individual seeds.
The first seed heads of the season are known as “primaries”. They are always the largest in diameter and produce the most and the largest seeds. Each successive wave produces seed heads that are just a bit smaller than the ones before.
As you might deduce from its Latin name, Sweet Fennel (Foeniculum vulgare dulce) is the original and classic form of this delightful herb. It is a tall stately plant reaching heights of well over 5 feet when in bloom. Its seeds are large, sweet and richly aromatic.
When speaking of fennel as a medicinal herb, Sweet Fennel is the variety of choice. Not only does it outrank the other varieties by its size and productiveness, but its seeds contain the highest concentration of medicinally active volatile oils. It also has the strongest, and some say the best, flavor of them all.
Florence Fennel (Foeniculum vulgare var. azoricum) is known as Finocchio in Italy and is occasionally mislabeled as “anise” here in the U.S. This fennel is known and grown around the world for its fleshy, celery-like lower stems, which grow so closely together as to create an oblong, slightly flattened, fan-shaped orb commonly referred to as a “bulb”. Fennel bulbs are sweet, tender, and crispy with a mild licorice or anise-like flavor.
Although Florence fennel is primarily cultivated as a vegetable, it will also produce flowers and set large, flavorful seeds, but only if the bulb goes un-harvested.
Of the three fennel varieties, my all-time favorite is the absolutely lovely and always impressive Bronze Fennel (Foeniculum vulgare var. ‘Rubrum’ or ‘Pupureum’). While its seeds are quite small (often less than one-sixteenth of an inch long) and relatively mild in flavor when compared to the other varieties, I actually prefer them for cooking because they are unobtrusive when added to foods.
I also love the way Bronze Fennel works as a focal point in the garden. The stems are mostly green with dashes of deep maroon or purple throughout. Early in the season, the leaves are dramatically colored with a mixture of deep blue-green and bronze hues. Of course, one can’t talk about Bronze Fennel without mentioning the literal profusion of delicate yellow flower umbels that light up this herb for weeks on end. This is a fennel that is more than pretty enough for the flower garden.
Sweet and bronze fennel are hardy perennials suitable for most climates but prefer long seasons of relatively warm, dry weather. Florence fennel is a little more demanding of water than the other two. While fennel can withstand a lot of abuse, they are not reliably perennial in areas that receive long periods of severe cold.
Growing fennel from seed is easy as long as you are using very fresh seed. Seeds stored for more than two years will likely not germinate.
Like other members of the Parsley Family, fennel has a long taproot and does not transplant well. For this reason, it is best to sow fennel ¼ inch deep directly in the garden. While seed can be planted in early spring, I prefer to sow seed in early to late winter. This method is known as ‘winter sowing’ and it has many advantages over traditional spring plantings, including earlier and stronger germination, seedlings that are well-adapted to spring weather, and lack of transplant shock. Once the seeds are sown, they will germinate when weather conditions are perfect for them.
After seedlings have reached 8 to 10 inches tall, they should be thinned to stand 6 inches apart with a final spacing of 12 to 14 inches for Florence fennel and 24 to 36 inches for seed bearing varieties.
Like many other herbs, fennel needs little in the way of supplemental fertilizer to keep it growing strong. Even if growing fennel in average soil, a weekly watering and a light side-dressing of bone meal around fennel grown for seed prior to flowering is all that is needed. When growing seed fennel, consider staking plants as the seed heads develop. For this, a light bamboo cage or trellis should do the trick.
While seed-bearing fennels are easy to care for, Florence fennel has a reputation as being fussy. It doesn’t need extravagantly wonderful soil, but it will bolt on a dime if a cool spring suddenly turns hot or the plants are not provided with a steady supply of moisture. One way to prevent premature bolting is by keeping the soil temperature as steady as possible. This is easily accomplished by applying a 1-inch layer of mulch when seedlings are about 6 inches tall and steadily increasing the depth as plants grow taller. Up to 6 inches of mulch applied early in the season will go a long way in keeping the soil cool and moist.
The mulch you apply in spring will also come in handy when the Florence fennel bulbs begin to mature. Simply pull enough mulch up and around the bulbs to block the sunlight from reaching them. Blanching keeps the bulbs light in color, crisp, and sweet. It also helps prevent dirt and grit from becoming entrenched in the tightly wrapped stems.
A Little Fennel Goes a Long Way
Gardeners who practice companion planting are well aware that some plants don’t like each other very much and will grow poorly if planted too close together. Fennel is one of those herbs that many garden crops (particularly bush beans, tomatoes and onions) just don’t like very much. That’s because fennel is an allelopathic plant whose roots and leaves produce a biochemical that can inhibit the growth of other plants nearby. This compound literally reduces any competition from unrelated plants by clearing the way for fennel’s own progeny. That being said, not all plants respond negatively to fennel. Indeed, the oregano, thyme and French sorrel growing alongside the bronze fennel in my garden don’t seem to mind it in the least bit.
By now, you probably realize that fennel is a very hardy and self-determined herb. In addition to its ability to thwart the competition, it also produces a plethora of tiny seeds that are easily scattered near and far. Because of this, fennel can and will become invasive if the seed heads are allowed to mature on the plant and shatter. To help reduce the chances of this happening, all seed heads should be gathered before they ripen.
As soon as the first few seeds in each umbel turn brown, snip off the entire head with a pair of scissors and place them in a large paper bag where they will continue to ripen and dry. Gather seed heads every few days until the entire harvest is complete. Once all of the seeds are brown and dry, they can be rolled between the palms to release them from their tiny stems.
It is often said that cilantro can be used to control the unwanted spread of fennel in the garden. And while I haven’t yet tried to prove or disprove this bit of garden lore, I can say with certainty that I’ve never had fennel growing in my cilantro.
For such a sturdy perennial, fennel is not oblivious to foul winter weather. In areas with very cold winters or repeated freeze-and-thaw cycles, fennel should be mulched heavily with straw or leaves to keep soil temperatures even and reduce the incidence of heaving.
If you are a tidy gardener who likes to remove old, dead growth for winter, you might be interested to learn that research indicates that allowing the dried stems of perennials to remain until the first spring growth emerges actually helps the plant survive winter’s cold and increases its overall health. If you feel compelled to tidy up the fennel bed for winter, try to wait until the plant has died back completely before cutting the stems to the ground.
Check back next week for Fantastic Fennel Part Two to find out more about a few surprising ways you can use fennel in the kitchen and how it can easily be used as a safe and effective herbal remedy for every member of your family!
Until then, Happy Gardening!
Show Me Oz | Living and loving life in the Ozarks!
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© Jill Henderson
Learn how to grow and use the world’s oldest, safest, and most medicinal herbs with this easy step-by-step guide! From starting seeds to preparing home remedies, The Healing Power of Kitchen Herbs is a treasured resource that you will turn to time and time again.
Jill Henderson is an artist, author, and the editor of Show Me Oz Her books, The Healing Power of Kitchen Herbs, The Garden Seed Saving Guide and A Journey of Seasons and Illuminati Agenda 21 can be found in the Show Me Oz Bookstore. Jill is a featured columnist for Acres USA and a contributing author to Llewellyn’s Herbal Almanac and her work has appeared in The Permaculture Activist and The Essential Herbal.
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