Milkweed is a plant best known as a specific host plant sought out by certain butterflies — notably the well-known Monarch Butterfly and lesser known Queen Butterfly.
It is also a wonderful plant for all sorts of nectar loving insects. Both Monarch and Queen Butterflies lay their eggs on milkweed which the caterpillars consume to develop into butterflies. And eat they do. They can strip a milkweed of all the leaves in a very short period of time.
Gardeners often find they need only plant one or several plants to attract butterflies to their Gardens, but if they want to raise many butterflies they quickly learn that they need more than a few plants. Too few plants, and the caterpillars quickly eat themselves out of house and home.
While there are more than a few species of milkweed, there are two commonly found in local nurseries, for sale as “butterfly garden plants,” or “butterfly weed.” Butterfly weed, Asciepias tuberosa , is a native perennial to the Southeast United States with orange or yellow flowers that appears in late summer and early fall.
The blooms attract Queen and Monarch butterflies and lots of other pollinators that seek out their nectar. But the larval or caterpillar form of Monarch and Queen butterflies need the milkweed to eat so they can complete the fascinating process of metamorphosis from caterpillar to adult butterfly.
The other commonly sold milkweed is the non-native Tropical Milkweed, Asclepsia curassivica. This quick growing and sometimes invasive plant seems to be the choice of most butterfly gardeners due to the ease of growing the plant. They are fast-growing plants that grow two to three feet tall and can spread out three feet wide. They usually flower from July through September and quickly form viable seed pods which contain easily germinated seeds. The leaves can grow four to six inches long with orange, red and yellow flowers, but the plants may not bloom freely until they are well established.
Infestations by yellow Milkweed Aphids are common but are easily controlled by spraying with soapy water. Be careful that the spray does not come in contact with the caterpillars, so they don’t fall victim to the spray. Many gardeners rely on ladybugs and other natural enemies of aphids and avoid spraying anything near a butterfly garden. Most butterfly gardeners choose to let nature take its course since these yellow aphids rarely compete with the monarch for food.
Other insect such as red and black Milkweed beetles can also be a nuisance. These can be picked off and thrown into a pail of soapy water if their numbers become too numerous.
The best sites to plant milkweeds is in full or partial shade in almost any soil. The plants tolerate well-drained but not heavy soil. The native milkweed, A. tuberosa, can be found growing along the southernmost areas of the U.S. but also in coastal regions as far west as California and as far north as Canada. The non-native A. curassivica is a tropical plant and is found mostly in Florida, Texas or California as a perennial, but can grow in most of the United States as an annual. Like Lantana, an excellent pollinator yet invasive plant, Milkweed is also a poisonous pasture plant to cattle.
Milkweeds get their common name from the milky sap they exude when the stem is cut. This sap can irritate the skin or eyes so handling with gloves is a good idea in case you are one of those persons that are sensitive to it.
The toxins in the milkweeds sap also makes the caterpillars and butterflies unpalatable to birds and other predators. For this reason other butterflies, such as the Viceroy Butterfly mimic the Monarch and thus are less bothered by predators.
For information on planting a butterfly garden you can read this University of Florida article, Butterfly gardening in Florida at http://edis.ifas.ufl.edu/uw057 .
Where to Buy Milkweed
To purchase Tropical Milkweed and many other butterfly nectar and host plants be sure to come to the Highlands County Master Gardeners 1st Annual Garden Festival and Plant Sale on November 17th at the Bert Harris Agricultural Civic Center in Sebring. Not only will you have an opportunity to purchase plants but you can talk to our butterfly gardening experts and take home lots of literature on gardening for butterflies.
For more information call the Extension office at 863 402-6540.