Bronze
Foeniculum vulgare
Bronze is an heirloom fennel variety prized for its distinctive copper-bronze foliage that sets it apart from traditional green fennel. This productive herb reaches maturity in 50-60 days and develops a sweet anise flavor that evolves from mild in young plants to rich and intensely fragrant when fully mature. The bronze coloring becomes more pronounced as the plant matures, making it visually striking in gardens. Bronze fennel is valued both as a culinary herb for its superior flavor depth and as an ornamental addition to herb and perennial gardens, thriving in full sun with well-drained soil.
Harvest
50-60d
Days to harvest
Sun
Full sun
Zones
4–9
USDA hardiness
Height
4-6 feet
Planting Timeline
Showing dates for Bronze in USDA Zone 7
All Zone 7 herb →Zone Map
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Bronze · Zones 4–9
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | April – May | June – July | — | July – October |
| Zone 4 | March – April | June – July | — | July – October |
| Zone 5 | March – April | May – June | — | June – October |
| Zone 6 | March – April | May – June | — | June – November |
| Zone 7 | February – March | April – June | — | June – November |
| Zone 8 | February – March | April – May | — | May – December |
| Zone 9 | January – February | March – April | — | April – December |
| Zone 10 | January – January | February – April | — | April – December |
Complete Growing Guide
Vigorous and uniform strain is slow to bolt. Nonbulbing type. Leaves are a nice addition to salads, coleslaws, and dressings.Flavor in fennel develops and intensifies as plants mature. Very young plants (baby-leaf stage) will have a mild flavor, while mature plants (8-12" tall) will have a fuller fennel flavor. Edible Flowers: The florets are used to garnish savory dishes, and pair well with fish, potato, tomato, and beef dishes. Flavor is of sweet anise. According to Johnny's Selected Seeds, Bronze is 50 - 60 days to maturity, tender perennial, open pollinated. Notable features: Organic Seeds, Plants, and Supplies, Attracts Beneficial Insects.
Light: Full sun (6 or more hours of direct sunlight a day). Soil: Clay, High Organic Matter, Loam (Silt), Sand. Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist, Occasionally Dry. Height: 4 ft. 0 in. - 6 ft. 0 in. Spread: 1 ft. 6 in. - 3 ft. 3 in. Spacing: Less than 12 inches. Maintenance: Low. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.
Harvesting
Bronze reaches harvest at 50 - 60 days from sowing per Johnny's Selected Seeds. Expect 8-12" at peak.
Aromatic seeds follow the flowers in late summer, early fall.
Color: Green, White.
Garden value: Edible, Fragrant
Harvest time: Fall
Storage & Preservation
Bronze fennel fronds keep best in the refrigerator crisper drawer in a breathable plastic bag, ideally between 35–40°F with moderate humidity; expect 5–7 days of acceptable freshness before wilting becomes pronounced. For longer preservation, freeze the finely chopped fronds in ice cube trays with a little water, or dry them slowly in a warm, well-ventilated space until brittle, then store in airtight jars away from light. The seeds—which develop after flowering—dry excellently when hung in paper bags; they'll remain viable for 3–4 years in cool, dry conditions. Bronze fennel's darker pigmentation makes it particularly ornamental in dried arrangements, so consider preserving some whole frond stems for visual appeal alongside culinary use. Fermentation is less common but possible; lacto-fermented fronds develop complex flavor in 1–2 weeks at room temperature.
History & Origin
Bronze is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.
Origin: Southern Europe and the Mediterranean
Advantages
- +Slow to bolt, making it reliable for extended harvesting periods
- +Vigorous and uniform growth ensures consistent quality across plantings
- +Flavor intensifies as plants mature, offering versatile culinary applications
- +Edible flowers provide garnish options with sweet anise flavor profile
Considerations
- -Nonbulbing type limits appeal to fennel bulb enthusiasts
- -Requires 50-60 days to maturity, extending time to first harvest
- -Mild flavor at baby-leaf stage may disappoint anise-flavor seekers
Companion Plants
Chives and French marigolds (Tagetes patula) are the two most practical companions to put near Bronze fennel. Chives (Allium schoenoprasum) may deter aphids through their sulfur compounds — worth something since fennel does attract aphid colonies on new growth. French marigolds are planted for their root exudates, which suppress soil nematodes over a full season. Nasturtiums pull double duty: they draw aphids off the fennel as a trap crop and the flowers are edible, so they're not wasted space.
Keep fennel away from tomatoes, bush beans, and kohlrabi. Fennel produces allelopathic compounds — anethole being the primary one — that inhibit germination and root development across a wide range of vegetables. Tomatoes are particularly sensitive, showing stunted growth even at 18-inch separation. The simplest fix is to give fennel its own dedicated corner at least 2 feet from any vegetable bed, and most of these conflicts stop being a problem.
Plant Together
Chives
Repels aphids and other soft-bodied insects with strong sulfur compounds
Marigold
Deters nematodes and aphids while attracting beneficial predatory insects
Nasturtium
Acts as trap crop for aphids and cucumber beetles, protecting bronze fennel
Yarrow
Attracts ladybugs and lacewings that prey on bronze fennel's common pests
Lavender
Repels moths and flies while attracting pollinators beneficial to seed production
Cilantro
Attracts beneficial wasps and hoverflies that control aphid populations
Basil
Repels aphids and spider mites, enhances bronze fennel's aromatic properties
Dill
Attracts beneficial insects like parasitic wasps that control bronze fennel pests
Keep Apart
Tomatoes
Bronze fennel can stunt tomato growth and alter fruit flavor negatively
Bush Beans
Fennel's allelopathic compounds inhibit bean germination and growth
Kohlrabi
Bronze fennel secretes compounds that can stunt brassica family growth
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #172232)
Pests & Disease Resistance
Common Pests
Swallowtail butterfly caterpillars, spider mites, aphids
Diseases
Root rot in poorly drained soil, powdery mildew in humid conditions
Troubleshooting Bronze
What you'll see, why it happens, and what to do about it.
Stems blackening at the soil line, plant wilting despite moist soil
Likely Causes
- Root rot — most often Pythium or Phytophthora spp. in waterlogged or compacted soil
- Planting in a low spot where water pools after rain
What to Do
- 1.Pull the plant and check the roots — if they're brown and mushy below the crown, the plant is done; remove it and don't replant fennel in that spot
- 2.Amend the bed with 3-4 inches of coarse compost worked in to improve drainage before next season
- 3.If the problem is chronic, raise the bed by at least 6 inches or move fennel to a spot with a natural slope
White powdery coating on leaves and stems, usually showing up mid to late summer
Likely Causes
- Powdery mildew — caused by Erysiphe spp., favored by warm days, cool nights, and poor airflow
- Crowded planting at less than 12 inches spacing that traps humidity around the foliage
What to Do
- 1.Cut out the worst-affected stems at the base and bin them — not the compost pile
- 2.Space plants at least 12-18 inches apart and keep weeds cleared so air moves through the bed
- 3.Water at the base of the plant rather than overhead; NC State Extension's disease management guidance points out that prolonged leaf wetness is what powdery mildew needs to get a foothold
Foliage stripped almost completely, with fat green-and-black striped caterpillars visible on the plant
Likely Causes
- Black swallowtail larvae (Papilio polyxenes) — they target the entire Apiaceae family, and Bronze fennel's dense bronze foliage makes it a preferred host
What to Do
- 1.Hand-pick the caterpillars if you need to protect the plant — relocate them to a patch of wild carrot or parsley rather than killing them
- 2.A healthy 4-6 foot fennel plant can bounce back from heavy defoliation if the crown is intact; give it a deep soak and a light side-dress of compost after stripping
- 3.If caterpillars are a recurring problem, start a second cluster of 2-3 plants in June specifically as a sacrificial host
Frequently Asked Questions
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Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
- USDAUSDA FoodData Central
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.