Bronze fennel
Foeniculum vulgare 'Purpureum' · Apiaceae
A tall, smoky cloud of thread-fine, bronze-purple foliage that smells of aniseed, topped with flat heads of mustard-yellow flowers.
- Size
- 5 ft tall, 24 in wide
- Zones
- 4 to 9
- Light
- Full sun
- Flowers
- Grown for its leaves; flowers mid July to late August
- Pets
- No toxicity recorded
- Job in a bed
- Weaver
A bed built around bronze fennel
The planner designed this bed around bronze fennel when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why bronze fennel stands where it does.
The plants
- 1 Bronze fennel × 3, bronze leaves
- 2 Sea thrift × 13, pink
- 3 Sedum 'Lidakense' × 16, pink
- 4 Little bluestem 'The Blues' × 5, tan
- 5 Hybrid tea rose × 1, white
- 6 Slender mountain mint × 3, white
- 7 Broad-leaved grape hyacinth × 12, blue
- 8 Schubert's allium × 4, pink
Why this plant
- The only plant grown for its leaves. Leaf lasts all season, where a flower lasts a few weeks.
Why here
- Anchors a back corner. At 5 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to little bluestem 'The Blues' (3 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 3 plants in one clump. A single spire is too slight to hold a place alone, so here the accent is a clump.
Why now
- Here for its leaves, spring to frost. They cover the 14 weeks between early March and late November when nothing on the plan is in flower.
Planned as a cottage garden: 41 of the 41 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Pink, blue, tan and white make a cool, restful scheme. Hybrid tea rose and bronze fennel anchor the back corners of the bed: the tallest plants on the plan stand there.
The planner's own design check: 12 Excellent, 3 Good, 2 Satisfactory. It flags one thing to watch: Bronze fennel spreads aggressively. Each plant's details say more.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where bronze fennel goes in a border
At 5 ft it belongs at the back of a bed. In the planner's ten height classes it is tall (4 to 5 ft). It is airy enough to see through, so it can also come forward and veil what is behind it.
Its job: weaver. A light, airy plant threaded singly between sturdier ones to knit the planting together.
The finest texture available at this height: plant it among roses or bold leaves and look through it. It feeds swallowtail caterpillars. Cut off the seed heads, or it will be everywhere.
- A see-through haze in the middle of a border
- Herb and kitchen gardens
- Swallowtail butterflies
What to plant with bronze fennel
Plants recorded as good partners for it, and what each pairing does:
- English rose: adds the flowers, early June to early October.
- Purple coneflower: adds the flowers, late June to early September; low enough (3 ft) to stand in front of it.
- Tall verbena: adds the flowers, late June to mid October.
Questions about bronze fennel
Does bronze fennel need sun or shade?
Bronze fennel grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.
What zones does bronze fennel grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
How far apart should bronze fennel be planted?
20 in (50 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.
It grows 5 ft (150 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many bronze fennel plants do I need?
At 20 in apart, set out in staggered rows:
- 4 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 14 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, threaded between sturdier plants.
In the bed above, the planner used three in one group.
Is bronze fennel poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension and the ASPCA.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Is there a native plant like bronze fennel?
Bronze fennel comes from Southern Europe and the Mediterranean. These North American natives come closest to doing its job:
- Blue sage: the same job in a bed; 12 in shorter, flowers late August to mid October.
- Grey-headed coneflower: the same job in a bed; 12 in shorter, 4 in narrower.
- White sage 'Silver King': the same job in a bed; belongs in the middle, not at the back, 24 in shorter.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat bronze fennel?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will bronze fennel spread?
It seeds itself about; the risk of it taking over is high. Self-seeds very freely, and the species is listed as invasive in California, Oregon and Washington. Cut off every flower head before the seed ripens.
What does bronze fennel look like in winter?
Bronze fennel dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
Is bronze fennel good for bees and butterflies?
Bronze fennel is visited by pollinators, bees, butterflies and beneficial insects.
In these guides
- Deer-resistant perennials for full sun
- Drought-tolerant perennials for full sun
- Pet-safe plants for a sunny border
- Plants for butterflies
- Plants for bees
- Tall perennials and grasses for the back of a border
- Plants with purple and burgundy leaves
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Perennial
- Size
- 5 ft (150 cm) tall, 24 in (60 cm) wide
- Plant
- 20 in (50 cm) apart
- Height class
- Tall (4 to 5 ft)
- Place in the bed
- Back, or further forward: it is airy enough to see through
- Flowers
- Mid July to late August; flat plates; yellow
- Leaves
- Fine texture, herbaceous; bronze, purple
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 4 to 9
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
- Family
- Apiaceae
- Comes from
- Southern Europe and the Mediterranean
- Attracts
- Pollinators, bees, butterflies, beneficial insects
- Stands up to
- Deer, drought, heat, humidity, poor soil
Checked against NC State Extension, ASPCA poison lists and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.