LAND
Native vs Tropical Milkweeds
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When I interviewed 7 scientists who specialize in monarch butterflies, they all raised concerns about how Mexican/ Tropical Milkweed (Asclepias curassavica) can disrupt the migration of endangered monarch butterflies in the northern regions of America and Canada. Tropical milkweed is a perennial plant native to South and Central America but found in tropical and subtropical regions worldwide. It is known for its vibrant flowers and is favored by gardeners for attracting monarch butterflies. These seeds and plants are sold on the internet even at home centers and nurseries all over the world. However, those tropical milkweeds which are not native to the colder regions can have negative effects on migratory monarchs. Their extended blooming period can disrupt monarch migration and breeding patterns since the senescence of native milkweeds likely is one of the cues for the fall and time for migrations. Additionally, tropical milkweeds have other potential negative effects including parasites, and diseases for these monarchs.
As the practice of plating milkweeds is getting popular, we wanted to check public knowledge of tropical milkweeds. Therefore, we asked 103 participants to visually identify the pictures of local and tropical milkweeds. With the pictures of flowers, nearly 40 percent of people wrongly identified the tropical milkweed. Without saying the identification of seeds and pods is extremely difficult. Nearly 70% of participants could not tell the differences.
The majority of the native milkweed flowers are powder pink, greenish cream white, or off-white and relatively easy to identify. However, one of the native milkweeds of North America called the Butterfly Weed (Asclepias tuberosa) and Tropical Milkweed (Asclepias curassavica) resemble each other and both have bright orange flowers.
Here is how to identify Tropical Milkweed (Asclepias curassavica) from native Butterfly Milkweed:
Color of flowers:
The flowers of most popular tropical milkweeds are usually two colors; RED AND ORANGE (with an orange corona and red corolla). Also, the flowers of another popular tropical milkweed, Silky Gold, are yellow. On the other hand, the native butterfly milkweed has just orange flowers.
Sap: When the leaves or stem of tropical milkweeds are broken, it releases a milky sap.
Leaves: The plant has narrow and pointed leaves. While it prefers moist soils and thrives in disturbed areas, it is commonly found in gardens.
* if you are about to buy unknown plants on the internet or at a shop, it is best to read the tag, check on the internet, or use a plant identifying app for more accurate verification.
Milkweed identification guide:
