Taiwan Black Yardlong

Family: Fabaceae Legume

Silky, ink-dark pods unfurl in long, graceful spears—an arresting Taiwan Black Yardlong that turns from green to a near-black plum sheen as it matures.

The texture is crisp-tender with a pleasantly sweet, bean-forward flavor, ideal for roasting until lightly charred, stir-frying for quick gloss, or steaming for a fresh, snappy bite. Grow this standout for show-stopping harvests at about 60 days, when the pods are at their most succulent and most strikingly colored.

Light: Full SunMaturity: 60 DaysHabit: Clumping

Botanical illustration of Taiwan Black Yardlong

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

Milestone	Date
Start Indoors	Direct Sow
Last Frost	Apr 25th
Transplant / Sow Outdoors	Apr 25th
Harvest Begins	Jun 24th
Harvest Ends	Oct 16th

Crop Details

Trait	Value
Days to Maturity	60
Sun Requirements	Full Sun
Growth Habit	Clumping
Support Needed	Trellis
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	60
Min Night Temp (°F)	55
Harden Off (days)	Not Required

Culinary Notes

Chef's Note

These dark, silky pods cook fast: you want crisp-tender, not mush—high heat gives you that ink-plum sheen and a sweet, bean-forward snap. The flavor hugs savory umami and hot fat well, so they’re built for wok speed and caramelized edges rather than long, wet braises.

Best Uses

hot-wok stir-fry until glossy with blistered edges
roast at high heat for lightly charred, caramel-leaning pods
steam-then-splash with acid (vinegar or lime) to keep them snappy
quick blanch and toss into sesame oil with salt for a clean side

Flavor Profile

sweet, bean-forward flavor crisp-tender crunch silky, lightly fibrous pod texture roasty, near-nutty char notes

Kitchen Pairings

garlic ginger sesame oil soy sauce lime juice chili crisp

Frequently Asked Questions

What’s the most common pest or disease on Vigna sesquipedalis (yardlong/black asparagus bean), and what should I do?

A frequent problem is aphids, which cluster on new growth and can weaken plants and spread virus. Rinse plants with a strong jet of water, then spray insecticidal soap or neem oil in the evening, repeating every 5–7 days until colonies stop. If you see leaf spots or mildew-like gray growth, remove badly infected leaves and improve airflow by spacing plants so rows aren’t crowded.

How often should I water Vigna sesquipedalis during peak pod production?

During flowering and pod fill (around weeks 3–8), keep the soil consistently moist but not waterlogged—about 1 inch (2.5 cm) per week total, adjusted for heat and container size. Water deeply 1–2 times per week rather than frequent light sprinkling, and aim the water at the soil because wet foliage increases disease on this bean.

How can I tell when Taiwan Black yardlong pods are ready to harvest?

Harvest when pods are young, firm, and fully developed in length but still tender—typically around 60 days, often when pods are about 18–30 inches (45–75 cm) and easy to snap. If pods start looking thick/grooved and the seeds feel hard, they’re getting past prime; pick every 1–3 days during the main flush to keep plants producing.