Bloodflower, or Asclepias curassavica, is a plant native to the American tropics, which includes the Caribbean, Central America, and South America. Boasting stunning orange, yellow, and red flowers, bloodflower is widely considered one of the most beautiful varieties of milkweed, which has made it a popular addition to butterfly gardens across the United States as gardeners swap out their native milkweed for this tropical variety. This colorful plant is also commonly referred to as Mexican butterfly weed. The best time of year to plant bloodflower seeds is early fall. It generally has a fast growth rate and blooms from summer to fall.
|Botanical Name||Asclepias curassavica|
|Common Name||Bloodflower, tropical milkweed, Mexican butterfly weed|
|Plant Type||Perennial, shrub|
|Mature Size||3 ft. tall, 1–2 ft. wide|
|Sun Exposure||Full, partial, shade|
|Soil pH||Acidic, neutral to acidic, alkaline|
|Bloom Time||Summer, fall|
|Flower Color||Yellow, orange, red|
|Hardiness Zones||8–11 (USDA)|
|Native Area||Caribbean, Central America, South America|
|Toxicity||Toxic to animals and people|
Research has shown that bloodflowers can be harmful to monarch butterfly migration patterns when grown in states with frost-free winters. Ensure you are following all pruning recommendations for bloodflowers if you choose to grow them in warmer U.S. climates.
Bloodflower Plant Care
Bloodflowers are a low-maintenance plant, but there is one big consideration to be mindful of when choosing it for your garden. Research has shown that the use of tropical milkweed in gardens in or near the migratory paths of monarch butterflies can interfere with monarch migration and increase the spread of the protozoan parasite that is found in bloodflowers. This is especially true in states that are warm all year round because the bloodflowers remain evergreen and monarch butterflies will often choose not to migrate at all.
So, if you live in a warmer southern state and are looking to create a butterfly garden or enhance your existing garden with plants that will attract butterflies, consider planting native milkweed varieties instead of bloodflowers. There are also some extra measures you can take if you do plant bloodflowers in your garden to ensure that you are protecting the butterflies and gardening responsibly.
Bloodflowers grow best in full sun but can tolerate partial shade when grown outdoors. When choosing a spot in your garden for bloodflowers, select a location that receives plenty of direct sunlight throughout the day.
Bloodflowers are able to grow in a variety of different soil types and generally aren’t picky about where they grow. Above all else, make certain that well-drained soil is provided as bloodflowers do not like to be waterlogged.
Bloodflowers are considered drought-tolerant but will do best when consistent moisture is provided. Supplement regular rainfall with occasional watering if you notice that the plant is drying out significantly between rainfalls.
Temperature and Humidity
In most areas of the United States, bloodflowers are treated as annuals, although they are evergreen perennials in tropical climates. They are hardy in zones 8a to 11 and remain evergreen to zone 9b. Bloodflowers can tolerate both humid and dry environments but thrive with added moisture.
Bloodflowers do not require regular fertilizing as they can tolerate poor, nutrient-deficient soils well. If you are starting your bloodflowers from seeds, you may wish to fertilize the seedlings once they have become established to give them a boost at the beginning of the growing season, but this is not necessary.
The Silky Gold bloodflower (Asclepias curassavica ‘Silky Gold’) features large clusters of golden-yellow flowers.
Is Bloodflower Toxic?
As with other milkweed varieties, all parts of the bloodflower are toxic if ingested. This applies to people as well as to animals including dogs and cats. Livestock like horses and cattle are particularly at risk.
Symptoms of Poisoning
Symptoms of bloodflower ingestion in humans can include stomach upset, skin irritation around the mouth and lips, and burning of the throat and inside the mouth. The sap is also a skin irritant and can cause rashes upon contact. Make sure to wear gardening gloves when pruning bloodflowers and keep your pets at a safe distance.
Bloodflower poses the most danger to animals and can lead to kidney or liver failure, coma and even death. Symptoms of poisoning in animals can include vomiting, weakness, bloat, diarrhea, depression, decreased or increased heart rate, dilated pupils, and drooling.
Due to the fact that bloodflowers can interfere in the natural migratory pattern of monarch butterflies, it is recommended that they are never allowed to go to seed, especially when grown in states without harsh winters that would naturally kill them off. Cut back the plants in the fall to ensure they don’t go to seed. When grown in areas with mild winters, bloodflowers should be cut back every couple of weeks to ensure they do not flower year-round.