Description
Asparagus Mary Washington
Asparagus ‘Mary Washington’ (Asparagus officinalis) is a classic, long-lived green asparagus variety grown from crowns for faster establishment. Prized for its tender, spear-like shoots, it produces uniform, medium-thick green spears with creamy white flesh and tips that range from green to purplish. As an open-pollinated heirloom, ‘Mary Washington’ produces both male and female plants. Male plants typically produce more spears and do not form berries, while female plants develop small red berries, which are poisonous and should not be eaten. A reliable and productive variety, it delivers increasingly generous harvests as the crowns mature over time.
Native to Europe, northern Africa, and parts of Asia, asparagus thrives in regions with long, cool winters and mild summers. Rich in vitamins A, C, E, and K, folate, and fibre, it’s a nutritious addition to any productive garden. ‘Mary Washington’ establishes more quickly than seed-grown plants. A light harvest may be taken in the second year after planting, though for optimal long-term yields, waiting until the third year allows crowns to fully establish. Spear production continues to improve over time as the plants mature.
Climate & Site Selection
Asparagus grows well in cool to subtropical climates. It performs best in full sun with some light afternoon shade in hotter regions. Choose a permanent location with deep, fertile, free-draining soil enriched with compost or aged manure. A neutral to slightly alkaline pH (6.5–7.5) is ideal.
Because asparagus can remain productive for 15–20 years, it should be planted in a permanent area with good drainage, away from spots likely to be disturbed. Raised beds are especially beneficial in heavier soils or poorly draining locations.
Growing Asparagus in Pots
Asparagus can be grown in containers, including deep pots or large trough-style planters, as long as they provide enough space for long-term root growth. As a perennial, it prefers to stay undisturbed, so choose a container that allows the crown to remain in place for several years. While container-grown plants may produce for a few seasons, yields often decline as space becomes limited, especially in smaller pots.
Keep soil consistently moist, fertilise after harvest, and mulch the surface in winter. In frost-prone areas, insulate smaller pots or move them to a sheltered spot. Larger containers offer better protection, but surface mulching still helps safeguard dormant crowns.
When to Plant
Plant crowns from late winter to early spring once the soil is workable, not waterlogged. This allows crowns to establish before growth begins.
If not planting immediately, store in a cool, dry, well-ventilated place (e.g. cupboard or garage). Keep the crowns in their original net bag or a breathable box without soil or moisture. Check them regularly and plant within a few weeks. Light mould on the roots may occasionally appear during storage or transit — this is not harmful and can be simply rubbed off before planting.
How to Plant
- Remove weeds and enrich the soil with compost and aged manure. Add balanced fertiliser.
- Dig trenches 20 cm deep, 30 cm wide.
- Make a mound in the trench base and spread roots over it.
- Space crowns 60 cm apart; allow 1.2–1.5 m between rows (or 90 cm–1 m in raised beds).
- Cover crowns with 5–7 cm of soil, but never cover the tip. Water in.
- As shoots appear, gradually backfill, keeping tips exposed.
- Mulch to conserve moisture, regulate temperature, and suppress weeds.
Life Cycle
- Year 1: No harvest. Let all spears grow into ferns.
- Year 2: Lightly harvest thicker spears for 2–3 weeks. Let others fern out.
- Year 3+: Full harvest for 6–8 weeks, extending up to 10 weeks as plants mature. Stop harvesting once spears become thin.
Supporting Ferns
By summer, ferns grow tall and may lean or snap in the wind. Support with stakes, twine, or a trellis to prevent damage and reduce disease.
Care & Maintenance
Keep beds free of weeds, ideally by hand, to protect the shallow roots. Water deeply and consistently, especially during active growth and in dry conditions. After the final harvest, fertilise to support strong fern growth. Once the ferns have fully yellowed and dried out—usually in late autumn or winter—they can be cut back to just above ground level to tidy the bed and reduce pest and disease risk. Refresh mulch in winter to help insulate crowns in cooler areas and shield roots from heat in warmer regions.
Seasonal Care
- Spring: Spears emerge; begin harvest.
- Summer: Spears grow into ferns; leave them intact.
- Autumn: Ferns yellow; cut back when fully browned.
- Winter: Dormant. Mulch and compost. Divide if needed.
Harvesting
Start light harvests in the second year and full harvests from the third. Spears emerge in spring and can be harvested for up to 10–12 weeks from mature plants. Cut when 15–20 cm tall and pencil-thick. Check every few days to avoid woody growth. Reduce watering near the end of the season and stop completely two weeks before the final harvest. Yellowing, floppy tops indicate dormancy.
Division
Divide crowns every 8–10 years in winter if growth declines or plants are overcrowded. Use a sharp spade and replant immediately.
Pests & Diseases
- Slugs/snails: Common in wet weather. Use traps or barriers.
- Crown rot: Avoid waterlogged soil.
- Rust/Fusarium: Improve airflow, remove affected ferns, and don’t replant in infected soil.
Companion Planting
Grow asparagus in its own bed. Strawberries nearby make good companions and attract beneficial insects. Avoid planting shallots or other alliums too close, as they may compete for nutrients.
Safety
Only the spears of Mary Washington are edible. The ferns may produce small red berries, which are poisonous if eaten. Keep children and pets supervised around the plants. If any part other than the spears is consumed, seek medical or veterinary advice immediately.
Supplied as dormant crowns.