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A Monarch Butterfly rests on Blue Porterweed inside a butterfly house. Photo by David Austin

Milkweed, Food for Butterflies

By David Austin with co-author Master Gardener, Lesa Morey.

Milkweed is food for butterflies
An Adult Queen Butterflies visits a Tropical Milkweed at the same time as a Monarch, lower left. The Queen Butterfly, upper left, is in full display.

An Adult Queen Butterflies visits a Tropical Milkweed at the same time as a Monarch, lower left. The Queen Butterfly, upper left, is in full display.

Milkweed is a plant best known as a specific host plant sought out by certain butterflies; notably the well-known Monarch Butterfly and lesser considered 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 eat 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.

A larger Tropical Milkweed is stripped clean of it's leaves by caterpillars. Photo by David Austin

A large Tropical Milkweed is stripped clean of it’s leaves by caterpillars. Photo by David Austin

 

Popular Milkweeds

While there are more than a few species of milkweed, there are two commonly found in local nurseries. For sale as “butterfly weed”, Asclepsia tuberosa , is a native perennial to the Southeast United States with orange or yellow flowers.  looms 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, which is also known as Scarlet Milkweed. 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.

A Monarch Butterfly larvae, dripping with morning dew, crawls along a Tropical Milkweed stem. The Queen larvae, which looks a lot like the Monarch's has an extra set of antennae. Photo by David Austin

A Monarch Butterfly caterpillar, dripping with morning dew, crawls along a Tropical Milkweed stem. The Queen caterpillar, which looks a lot like the Monarch’s, has an extra set of antennae like sensory tentacles about a quarter of the way down from its head. Photo by David Austin

Let nature take its course

Infestations by yellow Milkweed Aphids, are common but easily controlled by spraying with soapy water. If you are not familiar with them they appear as rows of small yellow balls hanging onto the newest growth. Be careful that the spray does not come in contact with the caterpillar so they don’t fall victim to the spray. I recommend relying 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 caterpillars 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.

Many other butterflies and insect choose Milkweed as a nectar source. Here aorange Julia butterfly enjoys a sip of this Tropical Milkweed. Photo by David Austin

Many other butterflies and insects choose Milkweed as a nectar source. Here a Julia butterfly enjoys a sip of this Tropical Milkweed. Photo by David Austin

Milkweed is easy to grow

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 established itself in Florida, Texas or California as a perennial but can grow in most of the United Sates as an annual.  Like non native Lantana, an excellent pollinator yet invasive plant, Milkweed is also a poisonous pasture plant to cattle.

Wear your gloves!
A lizard quietly sits on a milkweed stem and waits to make a meal of an unsuspecting pollinator.

A lizard hides on a milkweed stem and waits to make a meal of an unsuspecting pollinator. Photo by David Austin

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 such as birds. However, lizard and frogs do not seem to be bothered by these toxins. 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 .

Purchasing Milkweed

Many garden centers and nurseries carry Milkweed. The Tropical Milkweed is more commonly found and the easier to grow of the two plants. Remember, a couple plants are not enough to actually many raise caterpillars to adults. I recommend at least 10 plants or more if that is your goal.  There is a fear that milkweed from some stores may have been sprayed with chemicals. Perennial growers are quite familiar that these plants are bought for butterfly gardens and are careful to not use lingering pesticides. I’m sure the arguments will ensue on this one but in my experience, this line of thinking is a fallacy. 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, 2018 at the Bert Harris Agricultural Civic Center in Sebring.  You can host and nectar plants, plus get information from our butterfly gardening experts. Bring a tote so you can take home lots of literature on gardening for butterflies.  For more information call the Extension office at 863 402-6540.

Need answers?

Have a plant problem, a bug to ID, or any other horticulture related problem? Come see us at the Master Gardener help desk in the UF/IFAS Cooperative Extension office. We are at 4509 George Blvd., Sebring in the Bert Harris Agricultural Civic Center. Master Gardeners are on duty from 9:30 to 3:30, Monday through Friday.

Like my Hometown Gardener page on Facebook and stay up with the latest horticulture info in Florida’s Heartland.

Read Highlands County Extensions other blogs at http://blogs.ifas.ufl.edu/highlandsco/

Save the Date for the 2018 Garden Festival by the Highlands County Master Gardeners. November 17th at the Bert J Harris Agricultural Civic Center in Sebring, Fl. Watch the trailer! For information or to be a vendor email me at davidaustin@ufl.edu

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