Green milkweed (Asclepias viridis)

Overview

Asclepias viridis, commonly known as Green milkweed, is a highly valuable, low-maintenance native perennial for ecological landscaping projects across the central and eastern US. This species features unique, subtle green flowers with contrasting purple hoods, setting it apart from more common, brightly colored milkweeds. Its stature is modest, typically reaching 1.5 to 2.5 feet tall, making it suitable for integrating into borders without overwhelming surrounding plants.

A crucial benefit of establishing Asclepias viridis is its foundational role in supporting Monarch butterfly populations. As a host plant, the leaves are essential food for developing Monarch larvae, making this Green milkweed a must-have for dedicated pollinator gardens. Beyond wildlife support, the plant thrives in challenging conditions, tolerating drought once established and requiring minimal stewardship.

This perennial spreads gently by rhizomes and readily self-seeds in ideal environments, allowing garden areas to naturally naturalize over time. Gardeners looking to foster native biodiversity while maintaining drought resilience should prioritize the inclusion of Asclepias viridis in their planting schemes.

Fast Facts

• Plant Family: Apocynaceae
• Plant Type: Herbaceous perennial
• Native Range: Central and eastern United States
• Hardiness Zones: USDA Zones 5-9
• Size at Maturity:
  • Height: 1.5-2.5 ft
  • Spread: 1-2 ft
• Bloom Time: May to July
• Bloom Description: Green with purple hood
• Sun Exposure: Full sun
• Water Needs: Dry to medium
• Maintenance Level: Low

How to Grow

Establish Green milkweed in early spring or fall after the threat of hard frost has passed. Locate Asclepias viridis where it will receive full sun for the best bloom performance. It performs admirably in average, well-drained soils, handling dry to medium moisture regimes with ease, reflecting its inherent drought tolerance.

Once established, watering needs are minimal; allow the soil to dry out between infrequent deep waterings, particularly during hot, dry spells. Fertilization is generally unnecessary, as native plants thrive best without soil enrichment, which can often lead to weak, floppy growth. Pruning is limited primarily to removing spent seed heads if you wish to control self-seeding.

If you prefer fewer offspring in ensuing seasons, remove the seed pods before they split open in late summer or fall. Be aware that Asclepias viridis spreads via rhizomes, though this behavior is generally not aggressive or invasive. If you desire propagation, the plant is easily grown directly from seed sown directly into garden conditions.

Landscape Uses

The primary role for Asclepias viridis in the landscape is within ecological restoration projects, such as the establishment of meadows, prairies, and native plant areas. Its naturalizing tendency makes it perfect for softening the edges of a property or filling large, sunny, lower-maintenance spaces. Use it to create billowy masses that benefit pollinators throughout the season.

This plant also shines in butterfly gardens where the specific requirements of Monarch caterpillars can be met directly in visible spots near seating areas. While it is an excellent component for these larger naturalized settings, its manageable height also allows it to feature effectively toward the front or middle of a mixed perennial border where its green flowers provide subtle contrast.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Asclepias viridis, commonly called green or green-flowered milkweed, is an erect to sometimes decumbent glabrous perennial that grows to 20-30” tall on usually upright stems clad with mostly alternate, short-stalked, pointed, ovate-lanceolate, pale green leaves (to 2-5” long). Stems and leaves exude a milky sap when cut or bruised. It is native to glades, prairies, pastures, fields and roadsides from Ohio to Nebraska south to Florida and Texas. Tiny green flowers with purple hoods bloom in many-flowered axillary and terminal umbels from May to June. Flowers give way to seed pods (to 5” long) which split open when ripe releasing numerous silky-tailed seeds for dispersal by the wind. Flowers are a nectar source for many butterflies, and leaves are a food source for monarch butterfly larvae (caterpillars).

Tolerances

• Deer
• Drought

Potential Problems

This species typically presents no serious insect or disease problems, which contributes significantly to its low maintenance ranking. Control measures across the growing season are rarely necessary for Asclepias viridis. Plant owners should simply ensure the location offers sufficient drainage, as standing water is the most common stressor for most milkweeds.

Frequently Asked Questions

What hardiness zones is Green milkweed suitable for?

Asclepias viridis is perfectly suited for cultivation within USDA Hardiness Zones 5 through 9.

How large does Green milkweed grow?

When mature, Green milkweed typically reaches a height between 1.5 and 2.5 feet, spreading to occupy an area spanning 1 to 2 feet wide.

When does Green milkweed bloom?

This variety blooms early in the season, producing its distinctive green flowers with purple hoods from May to July.

What sun exposure does Green milkweed need?

For robust growth and optimal flowering, Asclepias viridis requires a planting location that receives consistent, full sun exposure throughout the day.

Conclusion

The Green milkweed (Asclepias viridis) offers exceptional value by combining low care requirements with vital ecological services, particularly for Monarch butterflies. Its unique coloration makes it an interesting addition to native garden accents or wide-open prairie plantings. Before planting, confirm your region falls within USDA Zones 5-9 and ensure the chosen site offers full sun and well-drained soil.

Wildlife Benefits

The most cited reason for incorporating Asclepias viridis into any landscape is its critical support for pollinators, specifically the Monarch butterfly. The foliage serves as the exclusive host plant for Monarch larvae, meaning caterpillars must consume these leaves to fuel their development and subsequent transformation.

Beyond hosting caterpillars, the flowers themselves, described as green with purple hoods, are efficient nectar sources for a variety of adult butterflies and beneficial insects. Maximizing the impact of your Green milkweed planting means letting the seed pods mature naturally so that wind dispersal can encourage future generations.

Companion Planting

Because Asclepias viridis demands full sun and tolerates dry to medium conditions, it pairs beautifully with other drought-tolerant prairie natives originating from zones 5-9. Consider pairing it with coneflowers (Echinacea species) or native grasses like Little Bluestem (Schizachyrium scoparium) which share similar soil and moisture needs.

These companions allow you to create a visually cohesive, low-input planting where water demands are consistent across the entire area. This holistic approach enhances the native habitat while making garden maintenance significantly easier across the growing season.