Nativars: Shopping at the Garden Center
Shopping at a garden center for native plants can be a pretty tricky experience, especially for those who are new to native plants. If you ask for a Coneflower, you might be shown one of those double-flowered cultivars (called nativar) which might look interesting but may not provide the same ecological services that the straight native would. Purple Coneflower (scientific name Echinacea purpurea) provides nectar, pollen, seeds, and leaves to many different types of animals. The cultivar or nativar most likely would not.
How to know what's a regular native and what's a cultivar? Labels are important. When shopping, have an idea of the latin/scientific name of the plant you want. For example, Echinacea purpurea shows that the plant is a straight native. Echinacea purpurea 'Razzmatazz' would mean it's a cultivar.
Studies are finally being done about the ecological functioning of cultivars; until then, the best bet and simplest thing to do is to buy straight natives when possible. Many of the studies focus solely on nectar amounts, and we all know a plant is more than just its nectar production. The other area of difficulty is that one cannot say ALL cultivars outperform regular natives in nectar output because that is simply not true.
The issues around nativars are complex; different people (even native plant enthusiasts) have different opinions on them. It's best for you to decide for yourself so below are some online resources.
ONLINE INFORMATION YOU CAN USE:
Wild Ones Nativar Statement
Beth Botts's Article on Nativars
Vincent Vizachero's Article: Nativars-- The Good, the Bad, the Ugly
(He has another article on the site in which he critiques Wild Ones's position on nativars.)
EcoBeneficial's Interview with Dr. Doug Tallamy