Blood flower (Asclepias curassavica)

Overview

Asclepias curassavica, commonly known as Blood flower, brings striking tropical color into the garden with its brilliant red-orange and yellow flowers. This herbaceous perennial is celebrated for both its aesthetic value and crucial ecological support, particularly for pollinators. While it thrives as an evergreen perennial in warmer zones, it is widely grown as an easy annual elsewhere, bringing reliable summer blooms.

This tender milkweed species typically matures between two and three feet tall, making it an excellent mid-border plant. Its low maintenance requirement and long bloom window from June through October ensure consistent visual appeal throughout the season. Gardeners often select Asclepias curassavica specifically to attract hummingbirds, bees, and butterflies to their landscape designs.

While highly attractive, gardeners must manage its self-seeding capabilities in warm climates where it naturalizes easily. Understanding the specific needs of this tropical native ensures successful culture, whether treating it as a short-term annual or a long-term perennial in appropriate hardiness zones.

Fast Facts

• Plant Family: Apocynaceae
• Plant Type: Herbaceous perennial
• Native Range: Caribbean, Central and South America, Mexico
• Hardiness Zones: USDA Zones 9-11
• Size at Maturity:
  • Height: 2-3 ft
  • Spread: 1.5-2 ft
• Bloom Time: June to October
• Bloom Description: Red-orange with yellow hood
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

For the best performance, plant Blood flower where it receives full sun, though it tolerates some light afternoon shade, especially in the hottest summer regions. This plant thrives in light, rich, evenly moist, well-drained soil. To establish new plants, start seeds indoors 8 to 10 weeks prior to your area’s last spring frost date. Harden off the seedlings carefully before transplanting them outdoors once all danger of frost has passed.

Watering should be consistent, aiming for medium moisture levels; however, Asclepias curassavica is noted to tolerate some periodic soil dryness once established. Maintenance is generally low. In areas outside of Zones 9-11, treat it as an annual, sowing fresh seed each spring for reliable summer color.

If growing Asclepias curassavica in containers, you can prolong its life by cutting it back and bringing the pots indoors to a bright, sunny location for the winter. Alternatively, in its native tropical zones, plants can become weedy and self-seed prolifically, so be aware of its naturalizing vigor. Always handle stems carefully, as the milky sap can cause skin irritation.

Landscape Uses

The vibrant coloration of Asclepias curassavica makes it a fantastic addition to cottage gardens or dynamic perennial borders where contrasting foliage and flower colors are desired. Its vertical structure (2-3 feet high) is well-suited for filling the middle ground of mixed flower beds, providing continuous structure from June through October.

Utilize this plant prominently in dedicated butterfly gardens where its dual role as a nectar source and larval host plant will maximize pollinator activity. Beyond living displays, the long stems make Blood flower a good choice for cutting gardens, yielding unique blooms for indoor arrangements. Even the resulting dried seed pods offer structural interest later in the season.

Consider grouping several plants together for maximum impact, pairing the intense red-orange tones with blues, purples, or silvery foliage for high contrast. In colder climates where it is grown as an annual, it functions beautifully in large patio containers alongside shorter annual companions.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Asclepias curassavica, commonly called blood flower, tropical milkweed, or scarlet milkweed, is a tender, evergreen perennial in the dogbane family. It is thought to be native to Central America, South America, and the Caribbean, but has escaped cultivation and naturalized worldwide in many tropical and subtropical areas. It typically grows as a subshrub to 2-3’ tall on upright stems clad with pointed, opposite, lanceolate leaves (to 6” long). Showy flowers with five sepals and five lobes appear in rounded axillary clusters, displaying red-orange petals with yellow hoods, attracting hummingbirds, butterflies, and bees.

Tolerances

• Deer

Potential Problems

This milkweed generally exhibits no serious pest or disease issues, though aphids can occasionally appear, potentially leading to sooty mold if populations are unchecked. The most significant consideration for Asclepias curassavica is its tendency to self-seed profusely in warm winter locations, where it is considered weedy or invasive in some regions. Because all parts of the plant exude a poisonous milky sap when cut or bruised, wear gloves when pruning or harvesting to prevent ingesting toxins or causing skin irritation. Gardeners should always confirm with local agricultural extensions which native milkweed species provide the best ecological benefit for local monarch populations instead of relying solely on this non-native variety.

Frequently Asked Questions

What hardiness zones is Blood flower suitable for?

Asclepias curassavica is winter hardy only in USDA Zones 9 through 11, where it can maintain evergreen perennial status.

How large does Asclepias curassavica grow?

This species typically reaches a height between 2 and 3 feet, with a spread of 1.5 to 2 feet at maturity.

What sun exposure does Blood flower need?

This plant performs best when situated in full sun to achieve the densest blooming; however, it will tolerate periods of light shade.

When does Asclepias curassavica bloom?

The flowering period for this plant is quite long, typically running from June all the way through October, offering vivid red-orange with yellow hood blooms.

Conclusion

The dazzling flowers and low maintenance requirements make Asclepias curassavica a rewarding choice for adding tropical flair and attracting beneficial insects. While Blood flower offers superior garden performance as an annual in cooler climates, be mindful of its self-seeding habits if growing in subtropical regions. Before planting, check your local ecological guidelines regarding non-native milkweeds and plan to start seeds indoors several weeks before the last expected frost.

Companion Planting

When integrating Asclepias curassavica into mixed beds, focus on companions that share its requirement for full sun and medium moisture, ensuring even watering across the board. Pairing the warm red-orange tones of Blood flower with cool blues, deep purples, or crisp whites creates a visually stunning contrast that highlights both sets of textures. Excellent companions often include zinnias, salvia varieties known for deep blue or violet spikes, or silvery-leafed herbs that complement its upright habit. Successful companion planting ensures that all species thrive under the same cultural umbrella, leading to a healthier, more vibrant display throughout the long bloom season.

Wildlife Benefits and Management

The primary wildlife benefit offered by this species of milkweed is attracting pollinators, specifically hummingbirds, bees, and butterflies, which rely on its nectar-rich flowers from early summer until frost. While Monarch butterflies may use Asclepias curassavica for egg-laying, experts strongly recommend planting locally native milkweed species instead, as they provide the most targeted and beneficial host resources for native Monarch larvae. Manage potential aphid outbreaks swiftly to prevent the secondary development of unsightly sooty mold on the leaves of your Blood flower plants.