Asparagus
Asparagus officinalis
Long-lived perennial that produces spears each spring for 15-20 years once established. Requires patience as you should not harvest for the first two years.
Overview
Companion Planting
Tomato
Basil
Parsley
Marigold
Calendula
Garlic
OnionToxicity
The red berries and foliage contain sapogenins that can cause vomiting, diarrhea, and abdominal pain if ingested; skin contact with the sap may cause dermatitis. The edible spears are safe when cooked.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Do not harvest any spears in the first two years to let crowns establish; mulch with straw to suppress weeds and retain moisture.
Common Pests
Common Asparagus Beetle (Crioceris asparagi)
Symptoms: Blue-black beetles with yellow spots chew spears and ferns, causing scarring, browning, and defoliation.
Treatment: Handpick adults and larvae daily into soapy water; apply neem oil or spinosad for heavy infestations.
Prevention: Remove fern debris after frost to destroy overwintering adults; encourage natural predators such as ladybugs and parasitic wasps.
Spotted Asparagus Beetle (Crioceris duodecimpunctata)
Symptoms: Reddish-orange beetles with black spots; larvae feed inside berries, weakening plants and reducing vigor.
Treatment: Handpick beetles and destroy infested berries; apply insecticidal soap if populations are high.
Prevention: Harvest spears promptly and remove volunteer seedlings to reduce berry production that supports larvae.
Slugs and Snails
Symptoms: Irregular holes and slime trails on young spears and fern foliage, especially in wet conditions.
Treatment: Set beer traps at soil level or apply iron-phosphate-based slug pellets around the bed.
Prevention: Keep the bed free of debris, water in the morning rather than evening, and use coarse mulch that slugs avoid.
Common Diseases
Fusarium Crown and Root Rot (Fusarium oxysporum f.sp. asparagi)
Symptoms: Yellowing and wilting of ferns, reddish-brown lesions on roots and crown, gradual stand decline over several years.
Treatment: Remove and destroy severely infected plants; no chemical cure exists for established infections.
Prevention: Plant resistant cultivars (e.g., 'Jersey Giant'), ensure excellent drainage, and avoid wounding crowns during cultivation.
Asparagus Rust (Puccinia asparagi)
Symptoms: Small orange-red pustules on stems and ferns that turn dark brown in late season, causing premature defoliation.
Treatment: Apply a registered fungicide (e.g., chlorothalonil or mancozeb) at first sign of pustules; remove and burn infected ferns.
Prevention: Plant rust-resistant varieties, space plants for good air circulation, and cut back ferns after the first hard frost.
Purple Spot (Pleospora herbarum / Stemphylium vesicarium)
Symptoms: Small purple-brown oval lesions on spears and fern needles, leading to early needle drop and weakened plants.
Treatment: Apply fungicide sprays during the fern growth period; remove and destroy infected plant material after the season.
Prevention: Improve air circulation with wider spacing, avoid overhead irrigation, and maintain good field sanitation.