My article last month talked about not only invasive exotic plants, but also Minnesota native plants that can become aggressive and take over a garden or prairie planting. I really try to be even-handed and truthful about natives versus exotics and I am a great believer in moderation.
I’m just not comfortable with those who have a “my way or the highway” approach when it comes to native plants. In recent years, there has been a big push to grow only native plants for the pollinators and for our environment. The real purists would have us only grow plants that have been grown from seeds harvested within a 50-mile radius of where we garden to preserve the local plant genetic footprint.
There are certainly many good reasons why native plants are usually a great choice, but I also think there are many non-native plants that benefit the birds, pollinators and other beneficial insects.
True, native plant
Douglas W. Tallamy, author of the book “Nature’s Best Hope,” believes that insects — especially caterpillars — are an important part of the nature equation and that 90% of insect herbivores are plant specialists. Monarchs and milkweed being the best example of that strong specialist connection.
Why is that important? He explains that most birds are insectivores and that 96% of birds rear their young on caterpillars. For example, it takes between 6,000 and 9,000 insects to rear just one clutch of baby chickadees.
But does that mean we can’t grow our favorite non-natives that are pollinator-friendly?
I just don’t think it is that cut and dried. Pollinators require nectar and pollen to survive and there are many non-natives that supply copious amounts of both. If you focus solely on natives — especially only on prairie plants — it is extremely difficult to have flowering from early spring to late fall which is what most pollinators need to thrive.
A study in Great Britain seems to agree.
The UK Royal Horticultural Society did an extensive four-year study with the project title “Plants for Bugs: Does the geographical origin of plants affect the abundance and diversity of the invertebrates they support?”
The final summary for the first paper was, “to support maximum number of pollinators it was recommended including a mixture of plants from different regions, with a focus on growing native plants but using exotic plants to extend the flowering season. The more flowers a garden can offer, the greater the number of bees, hoverflies and other pollinating insects it will attract.”
Master Gardener Diane Mueller, a monarch enthusiast, chooses natives over non-natives whenever possible, but also enjoys her dahlias especially ‘Bumble Rumble.’ Diane notes, “This is one of the most popular plants for bees that we have in the garden.”
Moderation is key
I agree that native plants have many outstanding attributes and should certainly be a part of your garden design, but non-natives can also have a place in your gardens. A good rule of thumb might be to grow one native plant for every non-native. Or even better, two native plants for everyone that isn’t native.
In other words, moderation. Grow some prairie plants, grow some host plants, grow some great nectar plants that may not be native. Please do your research though and don’t grow plants that are, or could become, invasive. I do draw the line at that!
Non-native pollinator favs
Mexican sunflower (Tithonia rotundifolia, annual)
Red salvia (Salvia coccinea, annual)
Tall verbena (Verbena bonariensis, annual)
Zinnias (Zinnia elegans, annual)
Catmint (Nepeta, perennial)
Red bee balm (Monarda ‘Colrain Red’, perennial)
Hot Lips turtlehead (Chelone lyonii ‘Hot Lips’, perennial)
Autumn Joy sedum (Hylotelephium ‘Herbstsfreude’, perennial)
UK RHS: Plants for Bugs Study: z.umn.edu/UK-RHS-study
Douglas Tallamy Webinar, Wild Ones: youtu.be/ARdYLamTA-M
Terry L. Yockey is a Goodhue County Extension Master Gardener.