Native vs Non-Native-Which is Better for Pollinators?

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Tithonia, Mexican Sunflower, native to Mexico and Central America, is one of the top insect drawing plants in my garden

Native Vs Non-Native

Native or non-native in the garden: Which is better? Simple- everyone knows the answer to that question…Natives of course! As gardeners, we have been bombarded with information about the value to wildlife of native plants and the more natives the better. But the definition of natives has always been fuzzy to me. Are natives plants that originated within our region, state, or North America? Or things that predate Europeans settling North America? Or does it mean plants indigenous to a particular habitat or ecosystem? And how about cultivars of native plants-like different varieties of Anise Hyssop which is a North American native? There are no easy answers to these questions.

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‘Pink Panther’ Anise Hyssop is a bee magnet
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Liatris is a great native wildflower that I grow for bee value

I have always been skeptical about the native plant zeal and ready to challenge it after my observations of over 50 years of gardening experience. My blog post on the benefits of planting Butterfly Bushes stirred up some controversy. I acknowledge that Butterfly Bush provides only nectar and not foliage value to caterpillars as a host plant. But I still urge people to plant Butterfly Bush because deer won’t touch it and the butterflies flock to it and I enjoy the plant for its beauty and ease of growth. There aren’t many flowering shrubs that deer leave alone which makes it valuable as a landscape plant.

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Pipevine Swallowtail on Butterfly Bush flower

I always deferred to the experts about native plants because anecdotal evidence is not the same as peer reviewed scientific articles.  So, I had no numbers to back up my belief gained from experience. Planting a diverse assortment of flowers- be it perennials, vines, annuals, trees, or shrubs or native and non-native to provide a healthy and beautiful habitat was always what I have practiced. My decisions on what to plant was determined by whether the plant was appropriate for the location and environment, not fussy, and that it wasn’t invasive.  Invasive means that a plant is spreading prolifically and undesirable or harmful to the habitat.

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A roadside field of invasive Purple Loosestrife,, Lythrum salicaria, originally from Europe
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Invasive Japanese Beetles feeding on Lythrum

Plants For Bugs Article

My longtime observations of planting a diverse selection of plants, both native and non-native, was recently backed up by an article, “Plants For Bugs: all in the mix” by Helen Bostock, who is a RHS Senior Horticultural advisor, from across the pond. Bostock says the average UK garden contains around 70 percent non-native and 30 percent native plants. I couldn’t find the U.S average, but I think it is probably very close to that same percentage. Bostock concludes that native use is on the rise, especially with the ‘back to the wild’ environmental movement, and ongoing education of home consumers of landscapes. I see it happening in my own practice of landscape designer with more and more requests for butterfly/wildlife friendly landscapes and less requests for manicured formal gardens. Gardens are still very unlike natural habitats but have a much greater diversity of plant species than their surroundings which have been degraded with development encroachment.

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Zinnias are not native to my area but pollinators love them

Bostock’s research concludes after studies spanning four years that a mix of plants from around the world may be the most effective way to sustain pollinators. This was no surprise to me. The native bandwagon has acquired mystical connotations in the past 10 years and claims that natives use less water, are disease free, and low maintenance have been made over and over.

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I am slowly removing turf and planting meadows with native plants on my property

But what role do garden plants (both native and non-native) play in supporting wildlife?  Views differ on whether planting native plants only is necessary for the most wildlife friendly garden. This was the question posed by the Wildlife Gardening Forum in the UK and they set up a field experiment designed to test whether the geographical origin of a plant affects the numbers and diversity of insects and other wildlife.

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Pollinating fly on mint flower

Conclusions

This is what the RHS study has concluded:

• Research reveals a mixture of native and non-native ornamental plants may provide the best resources for pollinating insects in gardens
• Native plants are not always the first choice for pollinators visiting gardens
• Non-native plants can prolong the flowering season providing an additional food source

Surprising results for many!

The basis of a garden’s health and vigor is determined by invertebrates, animals lacking a backbone. The more critters making a home or just stopping by for a refueling visit, the healthier your garden is to the environment and your health and well being.

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Dragonfly on waterlily

 Findings and Messages

For all pollinator groups on all treatments, greater floral resource, either native or non-native, resulted in an increase in visits. There was, however, a greater abundance of total pollinators recorded on native and near-native treatments compared with the exotic plots.

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Allegheny Vine, Adlumia Fungosa, is an endangered North American native, closely related to Bleeding Heart

Exotics were notable in extending the period of bloom which is really important to attract insects all season long.

The takeaway here – use site appropriate native plants when possible, understanding that some are a bit more boisterous than others, but add exotics where appropriate to enrich and extend the season. Gardens can be enhanced as a habitat by planting a variety of flowering plants, tilted towards native and near-native species.