Why We Can’t Sell Native Morning Glory Vines

Southeastern Arizona boasts a wonderful diversity of native morning glory vines of the genus Ipomoea, with a total of eleven species. Of these eleven native species, three of these have national and state conservation status. Ipomoea plummerae is a regional endemic that is a National Forest Service species of concern. I. longifolia is a state listed rare plant (S2 state conservation status) and Forest Service species of concern. And finally I. thurberi is a state listed very rare plant (S1 state conservation status), and a nationally listed very rare plant (N1 national conservation status). Ipomoea thurberi is found from less than six localities in the wild in the United States, which are all from Santa Cruz County in southeastern Arizona. In fact the designation for a N1 listed plant is “very rare/critically imperilled”, being from less than six localities in the wild. Despite the fact that these three plants are rare plants and species of concern, and that the rest of the Ipomoeas are in fact native plants - the Arizona Department of Agriculture has determined that these planted are state noxious weeds. Essentially this means that the state has determined that these plants are banned or illegal to sell. It is highly unfortunate that known invasive plants like Fountain Grass, Bermuda Grass, Tamarix/Salt Cedar, Tree of Heaven and African Sumac are all okay to grow & sell, but not these native plants. In fact, the reason why the above three species are rare/very rare or species of concern is because they are not invasive and have not spread outside of their isolated habitats. The Arizona Department of Argriculture’s decision is most likely based on experience with a non-native plant (Convolulus arvensis - field bindweed which is in the Morning Glory Family, Convoluvlaceae) that has been known to be invasive in irrigated areas. It is also possible that this fear of native Ipomoea species comes from an invasive hybrid of two native species known from the east coast of the United States. This could be one of the only cases in the country where a state simultaneously lists a particularly plant on the rare plant and prohibited noxious weed list. It is shocking to think of any native plant species being declared noxious weeds – in fact not even our native desert broom (Baccharis sarathroides) has been placed on the native plant list. At any rate, until the Department of Agriculture can view this situation from a factual basis and not just from a historic regulation, we will be unable to sell or cultivate these special native plants.