Plotwright
Home
Fennel
Habit (mature) · Ryan Hodnett / Wikimedia Commons · CC BY-SA 4.0
Limited coverage
Fennel
Foeniculum vulgare
A Mediterranean-native culinary herb grown for its anise-scented feathery foliage and seeds, both harvested for the kitchen. Upright branching stems rise 4-6 feet and carry flattened compound umbels of tiny yellow flowers in early summer, followed by aromatic seeds. The showy flowers draw butterflies and the foliage is a larval host for swallowtail caterpillars — but fennel self-seeds freely and has naturalized across North America, so spent flowering stems are best cut before seed sets.
Review: Source-backed
Climate fit: moderate (52/100)
Edible
Pollinator
Structure
Light
Full sun
Water
Moderate water
Mature size
48-72" tall · 18" apart
Hardy in zones
4a-9b
very cold to frosty winters
Summer heat range
Mild-Hot
mild to hot summers Interim Plotwright tier until the plant AHS range is authored.
Native in Illinois
No
Related products
Sponsored
Heat and sun protection
Shade cloth, shade hoops, cooling mulch, and heat-stress monitoring tools.
Search heat and sun protection on Amazon
Seed starting
Trays, cells, humidity domes, heat mats, grow lights, and seed-starting mix.
Search seed starting on Amazon
Drainage and aeration
Perlite, pumice, raised-bed mix, aerators, and drainage-focused containers.
Search drainage and aeration on Amazon
Transplanting and establishment
Trowels, transplant spades, starter fertilizer, root stimulators, and watering bags.
Search transplanting and establishment on Amazon
Pest and disease monitoring
Sticky traps, hand lenses, sprayers, disease-monitoring tools, and pest barriers.
Search pest and disease monitoring on Amazon
Plant support
Stakes, cages, trellises, ties, clips, arbors, and heavy-duty supports.
Search plant support on Amazon
Plotwright may earn a commission from purchases made through these links, at no extra cost to you.
A documented larval host for the Black swallowtail and 1 other species — caterpillars feed on its foliage before becoming the next generation.
Wildlife relationships
Cold hardiness
Now
Zone 6b
USDA
Chicago, IL · 1991-2020 average annual coldest day
Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer
Well-suited
2050
Zone 7b
Plotwright
Your zone + climate-model shift · SSP3-7.0 (regional rivalry)
Well-suited
In plain terms: cold winters — coldest nights typically around -3°F.
Well-suited today and still thriving in 2050.
Heat tolerance
Loading current AHS heat-zone and plant heat-fit data at your coordinates…
Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Fennel (Foeniculum vulgare). Retrieved 2026, June 5, from https://plotwright.garden/plants/fennel
Sources for every fact
Every fact on this page traces to a source. 18 fields cited18 source-backed.
Missouri Botanical Garden PlantFinder
Botanical research database
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
Growth stages
Lifecycle
Regional guidance
Success tips
Designer notes
Wikimedia Commons
Photo · CC BY-SA 4.0
Backs 1 field
Image
NC State Extension Gardener Plant Toolbox
University extension service
Community photos
The photos above are our reviewed reference set, curated for accuracy.
Plotwright
Climate-aware plant planning — every plant checked against your zone now and in 2050.
support@arteractive.co
© 2026 Plotwright