How to Grow Purple Asparagus

Purple Asparagus

Asparagus officinalis var. violaceus

vegetable

Purple asparagus is a vibrant cultivar of common asparagus featuring deep purple spears that turn green when cooked. The spears are typically thinner and sweeter than green varieties, with a more delicate flavor and tender texture. Once established, asparagus beds can produce for 15-20+ years with minimal care.

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Example Purple Asparagus timeline · Pittsburgh, PA (Zone 6b)

Plant Purple Asparagus
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Purple Asparagus
Late summer into fall

Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Purple Asparagus dates for your own zip code.

Growing Conditions

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Sun: Full sun, 8+ hours daily for best yield and spear quality

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Water: Moderate and consistent; 1-1.5 inches per week. Establish deep roots in first year by watering deeply but less frequently. Reduce watering in fall to harden crowns for winter.

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Spacing: 18 inches

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Days to maturity: 1095-1460 (plants begin productive harvest in year 2-3)

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Planting depth: 8-10 inches (crowns planted in furrows, gradually filled in as shoots emerge)

Soil

Type: Well-draining loamy soil, rich in organic matter

pH: 6.5-7.5

Amendments:

Compost or aged manure Bone meal for phosphorus Kelp meal for trace minerals Perlite or coarse sand if soil is clay-heavy

Growing Zones

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Zones 4-7 are ideal; thrives in cold winters and cool springs

3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b

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Growth Stages

Dormancy

Until soil reaches 50°F

Crowns are bare rhizomes with no visible growth; appear as gnarled, knobby structures.

Plant in early spring as soil becomes workable. Store bare-root crowns in cool conditions if planting is delayed. Soak crowns for 30 minutes before planting to rehydrate.

Establishment (Year 1)

Spring through fall (4-6 months)

Spindly shoots emerge and develop into feathery, fern-like foliage. Plants focus on root development rather than spear production.

Do not harvest spears in the first year; allow all shoots to mature into ferns. Remove dead ferns in fall. Mulch heavily around plants to suppress weeds and retain moisture. Side-dress with compost.

Development (Year 2)

Spring through early summer

Established crowns produce more robust ferns and stronger spears. Light harvesting may begin late in the season for a few weeks.

Allow first 2-4 weeks of spring growth to pass before light harvesting. Continue to limit harvest to 4 weeks to allow crown development. Maintain consistent moisture and fertility.

Full Production (Year 3+)

Spring for 6-8 weeks; summer for vegetative growth

Mature crowns produce abundant thick spears with the characteristic deep purple color. Ferny foliage grows tall (3-4 feet) by mid-summer.

Harvest for 6-8 weeks as spears reach 7-9 inches tall and snap easily. Cut spears at soil level or below. Apply balanced fertilizer or compost after harvest ends. Allow remaining spears to fern for photosynthesis and crown energy storage.

Dormancy Preparation

August through March

In fall, fern foliage yellows and dies back as plants prepare for winter. Seeds may develop if spears are left unharvested.

Cut back dead ferns in late fall or early spring, leaving no more than 2 inches of stem. Remove and compost fern material to reduce pest and disease overwintering. Apply 2-3 inches of compost mulch. Stop harvesting by late June in hot climates or early July in cool zones.

Companion Planting

Plan your garden →

Plant with:

Tomato Parsley Basil Comfrey Nasturtium Marigold Lettuce Spinach

Avoid planting near:

Onion Garlic Fennel Potato

Common Pests

Hand-pick adults and eggs in early morning. Use spinosad or neem oil spray. Plant trap crops like tansy nearby. Remove plant debris in fall.
Similar to asparagus beetle control; hand-picking and removal of berries (seeds) before they drop reduces populations.
Improve air circulation; avoid overhead watering. Cut back ferns completely in fall. Apply sulfur dust if disease appears. Choose rust-resistant varieties for future plantings.
and
Remove mulch close to spear tips. Use beer traps or copper barriers. Hand-pick at dawn/dusk. Apply diatomaceous earth.
Ensure excellent soil drainage; raise beds if needed. Avoid overwatering. Remove affected plants entirely. Rotate crops and do not replant asparagus in the same spot for several years.

Uses

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Fresh Cooking & Grilling

Culinary

Purple asparagus has a sweeter, more tender flavor than green varieties with subtle nutty notes. It is excellent roasted, grilled, steamed, or sautéed and retains a more delicate texture when cooked lightly. [source]

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Color & Visual Appeal

Culinary

The striking deep purple color adds vibrant visual interest to fresh salads, pasta dishes, and plated meals. The color typically softens to green upon cooking due to heat-induced chemical changes. [source]

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Folate & Antioxidant Source

Medicinal

Purple asparagus is rich in folate, glutathione, and anthocyanins, supporting cellular health, methylation reactions, and antioxidant defense. Regular consumption may support cardiovascular and cognitive health. [source]

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Long-Term Perennial Garden Investment

Household

An established asparagus bed is a permanent garden fixture requiring minimal annual input while yielding abundant fresh harvests for 15-20+ years, making it one of the most efficient perennial vegetables. [source]

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Pollinator & Beneficial Insect Support

Wildlife

When spears are left to fern and flower, asparagus produces small yellow flowers that attract pollinators and beneficial insects, supporting overall garden ecosystem health. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Begin harvest in late spring when spears are 7-9 inches tall and tightly budded with purple color. Spears snap or cut just below soil surface (harvest snap point is usually 1-2 inches below ground). Harvest every 2-3 days during peak season. Stop harvesting 6-8 weeks after first pick to allow crown recovery (earlier in hot climates). Spears are most tender and sweet if harvested before tips loosen or turn green from sun exposure.

Fun Facts

🌱 Purple asparagus varieties lack the enzyme that converts anthocyanins to green chlorophyll as readily as green types, retaining their deep purple hue longer when raw.
🌱 Asparagus has been cultivated for over 2,500 years and was prized by ancient Egyptians, Romans, and Greeks for both culinary and medicinal purposes.
🌱 A single mature asparagus crown can produce spears for 20+ years, making it one of the longest-yielding perennial vegetables—a well-maintained bed is a lifetime investment.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Compost Crown Cultivar Full Sun Mulch pH

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