How to Grow Bloodflower (Mexican Butterfly Weed)

A monarch butterfly sits on a Blood Flower (Asclepias curassavica) plant

NNehring / Getty Images

 

In This Article

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 Type Well-drained 
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
A close up shot of bloodflower (Asclepias curassavica) flowers getting ready to bloom.
Mauricio Acosta / Getty Images

Warning

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.

Light

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.

Soil

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.

Water

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.

Fertilizer

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.

Varieties

The Silky Gold bloodflower (Asclepias curassavica ‘Silky Gold’) features large clusters of golden-yellow flowers.



Pruning

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.