More Grist for the Natives versus Nativars Debate
Recently, the blog Humane Gardener published an interesting interview with Vermont ecological garden designer Annie White. For her doctoral research, White had conducted an experiment to determine whether pollinators had preferences for straight species native plants as opposed to named cultivars bred from native plants – “nativars”.
Her results were mixed. For seven of the twelve species tested, pollinators had a clear preference for the straight species. For four of the species, there was no difference between the cultivar and the straight species in terms of pollinator attraction.
And in one case, pollinators actually preferred the cultivar to the straight species.
Here are the specific plants tested by White:
The following plants showed a significant pollinator preference for the straight species over the cultivars:
- Purple Coneflower (Echinacea purpurea) v E. purpurea ‘White Swan’, ‘Big Sky’, and ‘Pink Double Delight’.
- New England Aster (Symphyotrichum novae-angliae) v S. novae-angliae ‘Alma Potschke’.
- Anise Hyssop (Agastache foeniculum) v A. foeniculum ‘Golden Jubilee’.
- Blue Wild Indigo (Baptisia australis) v B. australis ‘Twilite Prairieblues’.
- Sneezeweed (Helenium autumnale) v H. autumnale ‘Moerheim Beauty’.
- Ohio Spiderwort (Tradescantia ohiensis) v T. ohiensis ‘Red Grape’.
- Yarrow (Achillea millefolium) v A. millefolium ‘Strawberry Seduction’.
With the following plants pollinators were attracted equally to straight species and cultivars.
- Butterflyweed (Asclepias tuberosa) v A. tuberosa ‘Hello Yellow’.
- Smooth Penstemon (Penstemon digitalis) v P. digitalis ‘Husker Red’.
- Wild Bergamot (Monarda fistulosa) v M. fistulosa ‘Claire Grace’.
- Orange Coneflower (Rudbeckia fulgida) v R. fulgida ‘Goldsturm’.
And finally, pollinators preferred the cultivar ‘Lavendelturm’ to the straight species Culver’s Root (Veronicastrum virginicum).
What to make of all this? Well, if you want to have a pollinator-friendly garden, you should have a mix of straight species and cultivars. It’s not necessary to have straight species only.
In fact, in her interview Annie White says that she uses cultivars of native species, because sometimes you really want those people-pleasing qualities, especially more compact habit
Unfortunately, there is no hard and fast rule to determine which cultivars are most welcoming to pollinators. It’s generally thought that the greater the change in flower shape (for example, double flowers), the less welcoming a cultivar will be to pollinators.
However, the New England Aster variety ‘Alma Potschke’ changed only the color of the flower and not the shape, yet still saw a dramatic drop in visits from pollinators. So you never know.
In our garden, we have a mix of native straight species, cultivars, and exotic plants. We have no plans to change that, but will always try to maintain a substantial presence for the straight species natives.
That’s all for now.