Standley's amaranth: complete guide

Overview

Standley's amaranth (Amaranthus standleyanus), also known as Argentine amaranth and indehiscent pigweed, is a fascinating annual plant native to Bolivia, Paraguay, Uruguay, and Argentina. This species is less common in gardens than its European cousins but definitely deserves more attention for its unique appearance and hardy growing characteristics.

The plant is particularly valuable for wild gardens and permaculture designs, where it easily establishes through self-seeding. Standley's amaranth attracts pollinators and provides food for birds.

Appearance and Bloom

Standley's amaranth grows as a compact, upright plant with green foliage, typically reaching 40 to 80 cm in optimal conditions.

Characteristic green flower spikes appear from August to October. These are fuller and more prominent than Powell's amaranth. After flowering, dense seed heads form with unique indehiscent seed capsules (seeds that don't spontaneously open), providing extended bird food through winter.

The seed retention pattern is a major advantage: while other amaranths disperse their seeds, this variety holds seeds intact until birds consume them.

Ideal Location

Standley's amaranth grows best in fully sunny locations, requiring at least 6 to 8 hours of direct sunlight daily for optimal growth.

The plant is exceptionally wind and storm-resistant thanks to its compact growth habit.

Soil

The plant is highly adaptive, growing well in virtually all soil types. Research shows this species performs optimally in well-draining soil with neutral to slightly alkaline pH (7 to 7.5).

Standley's amaranth tolerates dry conditions well, making it ideal for low-maintenance, drought-resistant gardens.

Watering

Once established, Standley's amaranth is remarkably drought-tolerant. This makes it an ideal plant for water-saving gardens. During extreme drought (more than 3 weeks without precipitation), watering may occur, but is rarely necessary.

Young plants do require regular water during their first 4 weeks.

Pruning and Maintenance

Standley's amaranth requires minimal upkeep. Because seed heads remain intact, no cutting is necessary. The plant feeds birds well into December.

Let the plant fully mature for maximum seed availability for birds. A single plant can produce hundreds of seeds.

Maintenance Calendar

May to June: Seed sowing after last frost, or planting nursery seedlings. Minimal watering. July to September: Rapid growth. Little to no watering needed. August to October: Flowering and seed formation. No maintenance required. November to December: Seed heads feed birds. Plant dies after first frost. January to April: Plant removed; self-seeding setup.

Winter Hardiness

Standley's amaranth is not winter-hardy and dies at the first frost. This typically occurs in October or November, depending on weather.

Leave some plants in the garden for self-seeding. The plant reseeds itself, giving you volunteer plants year after year without replanting.

Suitable Combinations

Standley's amaranth pairs beautifully with ornamental grasses like Festuca and Miscanthus. Combining with wildflowers and other drought-tolerant annuals creates a natural, inviting landscape.

In borders, this amaranth works well alongside lavender, sage, and other Mediterranean herbs sharing the same heat and drought requirements.

In Conclusion

Standley's amaranth is an underrated gem for modern, sustainable gardens. The combination of beautiful green flowers, bird-friendly seeds, and exceptional drought resistance makes it a logical choice for environmentally conscious gardeners.

Available from specialized nurseries. Seed is easily ordered online and very affordable (approx. 1-2 euros). Once established, the plant self-seeds year after year.

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