WHAT TO PLANT
The Alabama Butterfly Atlas recommends and endorses the planting of native Alabama plants in the landscape. The list of garden-worthy native host and nectar plants is extensive. Many of these plants are not readily available at nurseries and big box stores. Check our News and Announcements section for native plant sales in your area. Scroll down for a list of mail order sources.
WHAT NOT TO PLANT
Unfortunately, there are plants that are commonly used to attract butterflies that we cannot condone or endorse because of the potentially harmful effects they have on our ecosystem as a whole. We ask you to carefully consider the unintended consequences of planting these species. The following information is provided to help you make informed decisions.
Butterfly Bush (Buddleia davidii)
Butterfly Bush, a native of China, is widely available to purchase, easy to grow, and butterflies are attracted to its nectar. Unfortunately, it also has invasive tendencies. The Center for Invasive Species and Ecosystem Health reports, “Buddleia davidii readily invades disturbed sites and riparian areas. Although butterflies will use this plant as a nectar source, their larvae cannot survive on it. By replacing native larval food source plants, butterfly bush can have a negative impact on wildlife.”
Butterfly bush is known to be invasive in other parts of the country; it is considered an emerging threat to natural areas in the mid-Atlantic region. There are scattered reports of escaped butterfly bushes in Alabama. Because you have not found it to be invasive in your own landscape does not mean that there is no problem. According to Dr. Doug Tallamy, author of Bringing Nature Home, "I hear the 'it's invasive here, but not over there' argument a lot…While it is invasive in many parts of the U.S., what's really important is that the plant has the ability to be invasive almost anywhere . . . . People who say butterfly bush doesn't move around are in the denial stage. I wouldn't fight it as much as I do if it weren't invasive, but butterfly bush just doesn't stay where we plant it."
Lantana (Lantana camara)
Lantana’s bright flowers attract nectaring butterflies, it is extremely easy to grow, and it is seldom bothered by pests or disease. But Lantana is listed as a Category I invasive exotic species by the Florida Exotic Pest Plant Council, which means that it is known to be "invading and disrupting native plant communities." It is also invading natural areas in Texas and is a huge problem in Hawaii. In Alabama, Lantana camara is listed as a Category 2 invasive plant, primarily due to its invasiveness in southern counties. Lack of cold hardiness may reduce its invasiveness further north, but according to EDDMapS it has been found growing wild as far north as Morgan County.
Part of the problem is that lantana reproduces both by seed and vegetatively. Flowers are produced throughout the growing season. Cross-pollination is common, but lantana blossoms are also able to self-pollinate. This trait makes it an extremely prolific seed producer, with approximately 12,000 fruits per plant. Birds and other animals that eat lantana fruit spread seeds across large distances. Normally germination is low; but when seed is passed through the digestive system of an animal, the germination rate is increased.
Vegetative reproduction occurs when lantana stems come into contact with moist soil, initiating root formation at the contact site. In other words, one plant can spread to form a thicket. To aid in the process, lantana produces chemical substances in its shoots and roots that inhibit the growth of plants that grow near it. When lantana invades natural ecosystems by establishing itself along creek banks and roadsides, native species are crowded out by the dense understory it creates.
Tropical Milkweed (Asclepias curassavica)
Advertisements extolling the virtues of Tropical Milkweed (Asclepias curassavica) seem to be everywhere, and it is often available in the nursery trade. This milkweed is beautiful, easy to grow, and attracts butterflies. But as advocates for native plant and butterfly conservation, we have serious reservations. Here are our concerns:
· Asclepias curassavica is a tropical species that is not native to the southeastern United States. It is not even native to the continental United States, yet it has established itself in Florida, Tennessee, Louisiana, Texas, and California;
· Tropical Milkweed is included in the Florida Natural Heritage Program’s Natural Areas Inventory as an invasive species and listed as a “high priority species for Early Detection and Rapid Response (EDRD).” The Alabama Plant Atlas notes that it is “commonly cultivated and sometimes escaping.” This may not sound alarming but according to Dr. Nancy Loewenstein, Executive Director of the Alabama Invasive Plant Council, based on its biology, Tropical Milkweed has potential to become a problem: “one of the best predictors of whether a plant will become invasive is if it is invasive somewhere else. This is especially true if it has invasive tendencies (e.g. a lot of easily spread seed, etc.).” With its ability to self-pollinate and its wind-blown seeds, Tropical Milkweed certainly fits this description;
· Well-meaning people choose to plant Tropical Milkweed because they think it helps Monarch butterflies. But recent studies indicate that A. curassavica is detrimental rather than beneficial to our Monarch population’s overall health. The problem is that Tropical Milkweed—at least when planted in warm environments like our Gulf Coast (and further north, depending on the severity of our winters)—doesn’t die back in the winter like native milkweed does. When presented with a place to lay their eggs year-round, many monarchs don’t leave it to make the trip to Mexico, and that causes problems. Researchers at the University of Georgia found that monarchs that did not migrate were more likely to be infected by the parasite Ophryocystis elektroscirrha (OE), which causes the butterflies to suffer from wing deformities, smaller body size, reduced flight performance, and shorter adult lifespans. This is a potentially devastating threat for eastern Monarchs. According to Lincoln Brower, a foremost Monarch authority, the research proves “absolutely definitively” that tropical milkweed is threatening to monarchs.
An article from Science magazine explains this problem in more detail: http://www.sciencemag.org/news/2015/01/plan-save-monarch-butterflies-backfires. For these reasons, the Alabama Butterfly Atlas does not encourage the planting of Tropical Milkweed.
Why take a chance? Let’s err on the side of caution and stick to our native host and nectar plants. In our world of rampant habitat loss, they desperately need our help to continue to find a niche in the landscape. Everything benefits from that!
Many people want to add native plants to their landcapes but are disappointed when they cannot find them in nurseries and garden shops. The following list is adapted from a document currently in development for the Birmingham Botanical Gardens Native Plant Conference (Oct. 26-28, 2017). These vendors specialize in native plants; those who will ship are noted as Mail Order. (Please be aware that this list is an informational tool: it is not intended to convey recomendation or endorsement of any vendor by the BBG or this website.)