Bronze Fennel

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Major parts of Bronze Fennel: flower, stalk, stem, and leaves

Fennel is an exotic herb by American standards, and Bronze Fennel is even more rare. In the landscape we could call it an Ornamental Carrot, since it belongs to that family. Dill is a cousin—perhaps you recognize the ferny fronds. Yellow Queen Anne’s Lace is another relative. One whiff of Bronze Fennel and the familiar anise-like scent transports us from the garden to the spice rack in the kitchen.

Surprisingly, a popular use of the herb has nothing to do with any of that. Bronze Fennel provides home and food for the caterpillars of Swallowtail butterflies and a number of other pollinators, so it is a frequent addition to wildlife gardens. From any angle, Bronze Fennel brings a number of interesting stories to the garden bed.

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Black Swallowtail butterfly caterpillars love Bronze Fennel


Most surprising to us is its leading role in the life cycle of the Swallowtail butterfly. Similar to the relationship between Monarchs and Asclepias, Swallowtails look for Fennel to provide a home, nursery and larder. They are not exclusive to the plant, but Swallowtails seek it out in large numbers. A common story we hear is about visits from these distinctive butterflies, and the striped caterpillars that appear later. Some gardeners plant Fennel just to encourage more visits.

Fennel, along with Dill and Parsley, form the backbone of butterfly herb gardens, grown primarily to attract beneficial pollinators. When allowed to flower, Bronze Fennel is an effective butterfly attractor for the neighborhood with lots of landing perches and feeding stations. Because herbs are so easy to grow, they are often used in children’s butterfly gardens to introduce them to this miniature cycle of life.

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Bronze Fennel blooms in the style of Queen Anne’s Lace


Flowers of Bronze Fennel look a lot like Queen Anne’s Lace, except they are more yellow and a little more open as well. Blooms start to appear in midsummer and last in succession until the plant is knocked back by the frost. Stems are very stiff so they make interesting vase arrangements, but they are also tall. If you wade into a thicket of Bronze Fennel, you will find the flowers come up to your chest.

We find, however, that the real appeal of Bronze Fennel is the smoky dark foliage. Like many plants, that color needs to be toasted in full blazing sun or close to it. Although Fennel thrives when shade comes across it, we start to see more green and less bronze.

This brings us to two interesting highlights. When the bronze shows up, a silver cast often appears in the leaves as well, outlining the ferny nature of the stems and leaves. Also, look for the emerging leaves—they punctuate the display like little foxtails burrowing within, popping up and then disappearing.

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Emerging leaves look like little foxtails among the silver highlights


For designers of wildscapes, meadows, and other natural landscapes, Bronze Fennel works just like Queen Anne’s Lace in the soil. It competes with the prairie grasses, establishes itself in disturbed soils, and handles both lean and hard dirt as well as the usual stuff. Logical companions would be other tall plants that have walked around the meadow once or twice like Solidago, Asclepias, Rudbeckia, Echinacea, or tall ornamentals such as Pennisetum or Millet.

If you are designing a bed we recommend a tight stand for a large, billowing display of ferny fronds. By itself, the plant grows about four feet in height, leaning out and around to a diameter of two or three feet. Bronze Fennel is hardy in Cincinnati so it dies back and returns the next season, but only for a few years. It has a short life as a perennial.

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A stand of thick stems supports a cloud of ferny leaves

Another choice is a mass planting. Fennels embrace their neighbors; stems lean on each other, leaves tangle among each other, and flower stems intertwine, all with that signature anise scent. If you want a bushier look give it a rough cut down to waist level, and the plant will grow back even more ferny and frilly.

Anchoring the entire superstructure are thick taproots that burrow straight down into the soil. They’re not carrot-thick but they’re strapping nonetheless. As a result, Bronze Fennel is more of a garden plant and not ideally suited for container work.

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Pick leaves while they are young for the best flavor


Bronze Fennel has the same licorice taste as traditional Fennel, so the two can be swapped out for each other. However, as a garnish on the plate Bronze Fennel, with its smoky dark tones, wins out—especially if you can pluck the new leaves while they still have their reddish cast. Both Fennel and Bronze Fennel have an unmistakeable aroma that exudes from leaf to flower to seed, making all parts tasty and desirable.

Fennel flavors many dishes—it’s a prized seasoning for river fish and savory sausages. It shares its anise-like flavor with Tarragon so the two are often used together in salad dressings. Fennel has sweet notes that balance out the spicy bite of Tarragon, so the two are like old friends on a teeter-totter: just enough of one is needed to match the other. You might be surprised to know that Fennel shows up in baked goods as well; the seeds add a different twist to rye bread when used in place of caraway seeds, for example.

If you grow Fennel for its flavor, pull back on the fertilizer and keep the soil dry and lean. A smaller plant concentrates more flavorful oils into its tissues, resulting in a harvest with a stronger scent and flavor. A nourished plant spreads those oils throughout more bulk so the flavor is milder. Young leaves have the best taste, as well as a more tender bite.

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A Swallowtail pupates on the stem of Bronze Fennel


Bronze Fennel is one of those plants that can handle several different roles despite its quirky nature and lanky stature. It has a place in an interesting herb collection, and it anchors down a butterfly garden for children—of any age! Bronze Fennel also delivers garden drama we look for in an Ornamental Herb: the height is tall, the scent is licorice, the texture is frilly, and several color schemes appear depending on sun exposure. For those who want their garden to be a true experience, Bronze Fennel immerses the visitor.

We sell Bronze Fennel in the 4.5-inch pot as part of our Herb Collection.