Herbs

Petroselinum crispum 'Flat Leaf'

Flat Leaf Parsley

ApiaceaeMediterranean, southern Europe

At a Glance

TypeBiennial
HabitMounding
FoliageDeciduous
Height12-24 inches (30-60 cm)
Width12-18 inches (30-45 cm)

Growing Zones

USDA Hardiness Zones

3 - 9
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Attracts Pollinators
Attracts Butterflies
Deer Resistant
Fragrant (moderate)
Container Friendly
Maintenancelow

Overview

Petroselinum crispum 'Flat Leaf' (Italian parsley) is a biennial herb in the carrot family (Apiaceae) reaching 12–24 inches (30–60 cm) tall with a 12–18 inch (30–45 cm) spread, grown primarily for its aromatic flat foliage. Stems are erect, smooth, grooved, branching. Leaves are pinnately compound with broad, flat, toothed leaflets (versus the tightly curled leaflets of curly parsley), dark green, 3–6 inches (8–15 cm) long. The flat-leaf form has a stronger, more complex flavor than curly parsley and is the preferred culinary type in Mediterranean and European cooking. Seeds are slow to germinate (14–28 days); soaking in warm water for 24 hours before sowing improves germination. First-year plants produce a dense rosette of foliage. In the second year, the plant bolts to a compound umbel 24–36 inches (60–90 cm) tall with small greenish-yellow flowers. Leaf flavor declines sharply once bolting begins. A host plant for black swallowtail butterfly larvae (Papilio polyxenes), which feed on the foliage alongside dill, fennel, and carrot tops.

Native Range

Native to the Mediterranean and southern Europe, cultivated for at least 2,000 years. Widely naturalized in temperate regions. In the Pacific Northwest, overwinters reliably in mild years and often completes its biennial cycle with second-year flowering.

Suggested Uses

Planted in herb gardens, salad gardens, vegetable gardens, containers (2+ gallon), and windowsill plantings. The primary culinary herb worldwide alongside basil. Used fresh in tabbouleh, chimichurri, pasta, soups, sauces, salads, and as a garnish. Flat-leaf type has stronger flavor than curly and is preferred in Italian, French, and Middle Eastern cuisine. A host plant for black swallowtail butterfly larvae. The slow germination and biennial life cycle are taught in herb propagation courses.

How to Identify

Distinguished from curly parsley (P. crispum var. crispum) by the flat, broad leaflets (versus tightly curled), the stronger flavor, and the darker green color. Distinguished from cilantro (Coriandrum sativum) by the flat, toothed leaflets (versus rounded, fan-shaped lower leaves), the stronger parsley scent (versus soapy/citrus cilantro scent), and the slower bolting habit. Distinguished from celery leaf (Apium graveolens) by the thinner petioles and the flat (versus V-channeled) leaflets.

Appearance

Size & Dimensions

Height1' - 2'
Width/Spread1' - 1'6"

Colors

Flower Colors

green
yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~3 weeks
J
F
M
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Summer
Biennial; bolts in the second year after vernalization. Compound umbels of greenish-yellow flowers bloom in June–July of the second year. Flowers attract swallowtail butterflies for egg-laying. Leaf harvest is the first-year objective; remove bolting plants or allow to flower for butterfly habitat and self-sowing.

Detailed Descriptions

Flower Description

Greenish-yellow

Foliage Description

Dark green, flat, pinnately compound with broad, flat, toothed leaflets; stronger flavor than curly types

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Requires 3-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.0(Neutral)
357912
Soil Types
loamsilt
Drainage
moist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Start seeds indoors 8 weeks before the last frost or direct sow 2–4 weeks before the last frost, 0.25 inch (6 mm) deep. Soak seeds in warm water for 24 hours before sowing to soften the seed coat and improve germination. Space 8 inches (20 cm) apart. Germination is slow (14–28 days). Harvest outer stems at the base when plants reach 6 inches (15 cm) tall, leaving the growing center. In the Pacific Northwest, parsley overwinters in mild years; mulch the crown with 2 inches (5 cm) of straw in USDA zones 7–8. Container culture (2+ gallon) is standard for windowsills and balconies.

Pruning

Harvest outer stems at the base, leaving the center growing point. Remove bolting flower stalks in the second year to extend foliage harvest, or allow to flower for swallowtail butterfly habitat and self-sowing. Cut to ground level in late fall if not overwintering.

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 2 gallons

⚠️ Toxicity Warning

Non-toxic

Planting Guide

Planting Methods & Timing

Planting Method

both

Indoor Start

8 weeks before last frost

Direct Sow Timing

2-4 weeks before last frost; soak seeds 24 hours before sowing to improve germination

Days to Maturity

70–90 days

Plant Spacing

8 inches

Companion Planting

Good Companions

tomato
asparagus
corn
rose

Avoid Planting With

lettuce
mint