A tender warm-season culinary herb native to tropical Africa and Asia; grown as an annual in most US climates for fragrant edible leaves and as a kitchen-garden staple. Sweet basil is the species behind Genovese, Thai, and most ornamental purple basils.
Review: Source-backed
Climate fit: narrow (10/100)
Edible
Container
Filler
Light
Full sun / Part sun
Water
Consistent moisture
Mature size
18-30" tall · 12" apart
Hardy in zones
10a-10b (perennial); annual elsewhere
mild winters
Summer heat range
Warm-Hot
warm to hot summers Interim Plotwright tier until the plant AHS range is authored.
Native in Illinois
No
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
Won't grow here
2050
Zone 7b
Plotwright
Your zone + climate-model shift · SSP3-7.0 (regional rivalry)
Won't grow here
In plain terms: cold winters — coldest nights typically around -3°F.
✕
Out of range today and still out of range in 2050.
Heat tolerance
°C
°F
Loading current AHS heat-zone and plant heat-fit data at your coordinates…
Where this plant fits
Suitable across 17 ecoregions — 11 climate-resilient through 2070 · 6 newly possible by 2070. Best matches first.
Plant after nights are reliably warm (above 50°F) — basil sulks in cold soil and will not recover well.
•
Pinch tips and flower buds often to keep the plant branching and the leaves productive.
•
If basil downy mildew is a recurring problem in your region, plant a mildew-resistant cultivar — NC State Master Gardener trials rate 'Prospera', 'Rutgers Passion', and 'Rutgers Obsession' highly for both resistance and flavor.
Lifecycle
Planting
Plant in full sun in moist, well-drained soil after the last frost. Tolerates part shade but flavor and vigor are best in full sun. Can be grown from seed or transplanted.
Transplanting
Move hardened-off starts on an overcast day; basil hates root disturbance during transplant shock.
Early growth
Transplant hardened-off starts (or direct-sow seed) after the last frost when nights are reliably above 50°F. Keep evenly moist; basil sulks in cold soil.
Maturity
Mature plants reach 18-30 inches tall and 12-18 inches wide depending on cultivar; small white-pink lipped flowers in whorled racemes appear in summer (pinch off to keep leaves productive).
Propagation
Direct seed or transplant from indoor starts. Stem cuttings root reliably in water for continuous indoor production.
Pollination
Self-fertile
Self-fertile — one plant produces viable seed without a partner. In gardens basil is typically pinched and harvested before flowering, but if allowed to flower the spikes attract bees and small pollinators.
Plants don't grow alone
Nectar forage
Bee
European honeybee (Apis mellifera)
Basil is typically pinched to suppress flowering for leaf production, so flower-driven wildlife relationships are uncommon in cultivation; when allowed to flower the spikes do attract small bees.
Nectar forage
Bee
Common eastern bumblebee (Bombus impatiens)
For people
Edible
A core culinary herb — fresh leaves are eaten raw and cooked across Mediterranean, Italian, Thai, Vietnamese, and South Asian cuisines. No part of the plant is toxic.
Edible parts
leaves, flowers
Culinary use
Fresh in salads and sauces (pesto), layered on pizza and bruschetta, infused into oils and vinegars, brewed as a mild herbal tea.
Pet toxicity
Non-toxic to dogs and cats per the ASPCA toxic-plant database.
Climate notes
•
NC State Extension lists Ocimum basilicum as USDA hardiness 10a-10b — perennial only in true tropics. Grown as an annual in zones 3-9 across most of North America.
•
Native to tropical Africa and Asia; will not tolerate frost or cold soil.
•
Pest pressure: aphids and Japanese beetles occasional. Disease pressure: fusarium wilt and basil downy mildew (BDM) are serious. NC Master Gardener trials identify several mildew-resistant cultivars.
•
Native to tropical Africa and Asia, this is a true heat-lover: growth stalls once nights fall below ~10°C, and frost damages it outright. It performs best through warm-to-hot summers; cool maritime climates without steady summer warmth leave it stunted and slow.
In the designer
Growth over time
18-30" tall · 12-18" spread
Annual crop reaches harvest size quickly.
Design roles: Edible · Container · Filler
Seasonal interest
Spring
Summer
Fall
Winter
Filled = the plant has seasonal interest · ▾ now = your current season
Appears in collections
Collection · 3 plants
Kitchen patio planters
A compact edible collection for containers, patios, and near-door harvesting.
Genovese basil
Lacinato kale
Coral bells
+3
Genovese basil
Lacinato kale
Coral bells
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). Genovese basil (Ocimum basilicum). Retrieved 2026, June 5, from https://plotwright.garden/plants/basil
Sources for every fact
Every fact on this page traces to a source. 18 fields cited — 18 source-backed.