So you're interested in growing perennials that offer food for birds and bees, and you go to the garden center, where you are directed to ornamentals that are labeled as native. You've read about exotic plants and how they often don't provide sustenance for wildlife that evolved with native plants. You purchase some lovely coneflowers and bee balms and head home to plant them, feeling great about helping critters in your yard.
Unfortunately there is a problem with this scenario that many gardeners are not aware of, and it involves the difference between straight species of native plants and the cultivated varieties of the same. By straight species I mean the wild version a plant before humans began selectively breeding it for certain traits. Cultivated varieties, or cultivars as they are commonly know, are developed when horticulturalists select for characteristics such as flower color and size, or plant height. Cultivars usually don't breed true from seed and are typically propagated vegetatively. Nativars are cultivars of native plants.
Cultivars offer spectacular colors and interesting blossoms. They allow gardeners with limited space to grow compact versions of tall, floppy plants. While there is nothing intrinsically wrong with cultivars, they may not offer the same benefits to wildlife as straight species plants. Some are sterile and therefore have no fruit or seeds. Some might have little nectar, or nectar that is inaccessible to insects due to odd flower forms. They might have plenty of easily gotten nectar that is ignored because insects fail to recognize the altered flower as a food source.
While a PhD student at the University of Vermont, Dr. Annie White spent three growing seasons investigating the attraction to pollinators of native species versus nativars. You can read about her research and find lots of useful information on her website
She found that in general pollinators preferred species to cultivars, and the more highly bred the plant, the less they liked it. In only one case did the nativar receive more attention from pollinators than the species.
Knowing that they might not be nurturing wildlife as much as you hoped, should you rip up all your nativars and start fresh with species plants? Before you do, know that it is often difficult to find non-cultivar plants for sale. If there is a native plant nursery in your area, start there. Ordering seeds online from a reputable source is also an option.
Before doing anything drastic, however, take the time to observe what is happening during the growing season. Then you can make informed decisions about the plants you want to grow. Your particular situation, for example, the size of your garden or yard, and it's location, should also factor in to your plant choices. More about that
The photos in this post are all nativars that attract a significant number of insect visitors, and I see no reason to remove them. My major complaint about many cultivars is the fact that when plants are selected for appearance only, other traits such as drought resistance or ability to tolerate poor soils, are negatively affected. Many beautiful but highly bred plants look spectacular for a season or two, then die off, or limp along pathetically until I lose patience and rip them out. Nativars that thrive in the conditions here and attract pollinators are always welcome.
The agastache has had more babies, so unless I find room for it, there will be more in the 2020 plant sale. Am also winter-sowing it in milk jugs as an experiment.
Thank you for commenting and contributing local gardening wisdom. The agastache pictured is from your garden! It is one of my all time favorite plants and there is usually a cloud of insects surrounding it.
Yes to this. As far as I have been able to tell, "Magnus" coneflower is as attractive to pollinators as the straight species--not so the double varieties. "Honeybee Blue" agastache (the one I found locally and passed on to the Marietta plant sale) is a pollinator magnet and seems to come true (or so nearly true as makes no difference) from seed. My beloved burgundy physocarpus attracts the tiny early pollinators but does not seem to attract the leaf-eating insects, which suggests that a green form of the plant would be preferable overall.