Do some flower shopping–either in a nursery or online–and you will quickly come across native cultivars. These are native flowers that have been selected or hybridized, to produce a desirable or different trait from the native. So for example, Echinacea purpurea (purple coneflower) is a native and Echinacea purpurea ‘Sunrise’ Big Sky (a yellow version) is a native cultivar. Native cultivars, (sometimes called nativars) have become popular in plant breeding because natives are known to be great for the garden and pollinators. Cultivars are so popular that it might be tough to find the true natives at your local nursery. Yet do native cultivars also feed the bees and pollinators as well? Or, put another way, do native cultivars make good bee flowers?
That was the question studied by Annie White, PhD, ASLA. I was lucky enough to hear her talk “How Native Plant Cultivars Affect Pollinators” in Cambridge. The results of her work should be shared with all gardeners and anyone who cares about the well-being of our pollinators. To see an overview of her work, go to pollinatorgardens.org
The Natives Win….Generally
White chose 11 native flowers, then matched each one with at least one native cultivar, and planted both varieties side by side, in two locations. She counted and noted which and how many pollinators were visiting each variety of flower. Of the 11 studied, she found that 6 were much less attractive to pollinators, 1 cultivar was preferred over the species, and 4 were just as attractive as the species. White concludes, “the best plants to support pollinators seem to be unmodified native species or cultivars that are minimally modified.”
Here is an example of one native and 3 of its cultivars.
Echinacea purpurea is the native flower and a classic here in North America. White determined that this flower had the highest pollinator rates of the four Echinaceas tested, by far.
Echinacea purpurea ‘White Swan’ (a personal favorite of mine), this cultivar happens to be the result of a mutation in nature, which is then selected and propagated. All bee visits were about half of all bee visits to the native Echinacea purpurea. Interestingly, honey bee visits to ‘White Swan’ were still high (though lower than Echinacea purpurea). I still recommend this flower.
Echinacea purpurea ‘Pink Double Delight’. Petals cover the access to nectar, and stamens (where the pollen sits) no longer exist. So like other double flowers, this flower provides very little, if any, food for bees.
Echinacea purpurea ‘Sunrise’ Big Sky. Bee visits were slightly higher than ‘Pink Double Delight’, but still dramatically lower than the classic Echinacea purpurea. Not a good food source for pollinators.
Some Notable Bee Flowers
White found the following flowers support the bees. If the bees fed from a cultivar, I have included that name as well. I indicated which type of bees (honey bees, bumblebees, and native bees) were attracted to each flower.
- Achillea millefolium (Yarrow), only native bees
- Aclepias tuberosa and A. tuberosa ‘Hello Yello’ (Butterfly weed), bumblebees only
- Agastache foeniculum and A. foeniculum ‘Golden Jubilee’ (Anise Hyssop), honey bees preferred the native, but bumblebees fed from both
- Baptisia australis (False Blue Indigo), bumblebees and native bees
- Echinacea purpurea and Echinacea purpurea ‘White Swan’, (Coneflower), all bees
- Monarda fistulosa (Bee Balm) and M. fistulosa ‘Claire Grace’, only bumblebees
- Penstemon digitalis (Beardtongue), and P. digitalis ‘Husker Red’, honey bees preferred the native, bumblebees and native bees fed from the native and cultivar about equally
- Rudbeckia fulgida and R. fulgida ‘Goldsturm’ (Black-eyed Susan), bumblebees and native bees
- Symphyotrichum novae-angliae (Aster), all bees
- Tradescantia chinensis (Spiderwort), honey bees
- Veronicastrum virginicum ‘Lavender Towers’ (Culver’s Root), honey bees and bumblebees, the cultivar ‘Lavender Towers’ was preferred over the native species
Did you notice that not all types of bees were feeding from each flower? White’s data also shows us (or reminds us) that bees feed on flowers differently. For example, honey bees did not feed on the following flowers (though other types of bees and pollinators did): Rudbeckia (Black-eyed Susan), Asclepias tuberosa (Butterfly weed), Monarda fistulosa (Bee Balm) and Baptisia australis (Blue Wild Indigo or False Blue Indigo). This is significant given that the first three of these flowers are commonly found on bee flower lists.
White’s work shows us the dominance of bees as pollinators. Within her site in Vermont, 86% of pollinators were bees (43% were bumblebees, 30% were honey bees and 13% were native bees.) Other kinds of pollinators accounted for just 14% of visits (6% flies, 4% were beetles & bugs, 2% were butterflies or moths, and 2% were wasps or ants.)
The Bottom Line for You
I dream of the day when plant breeders will test their new cultivars as a food source for pollinators before the plants are released to the public. Makes sense, right? In a world where our wild flowers are often not abundant enough to sustain our bees, we humans should know exactly what we are feeding them. Breeders could even grade each variety on well it feeds the pollinators, and which ones. Better yet, they could breed flowers for their ability to feed bees and pollinators. Ahh…now wouldn’t that be nice?
Until that happens, I recommend being cautious about native cultivars–unless you know the cultivar feeds the bees well. Let’s be honest; this may be challenging, as the natives are not always available. But it is a worthwhile conversation to have with your nursery. If your goal is to feed the bees and or pollinators, they should be able to find the right plants for you. There is a second reason why you should be cautious about cultivars. Native cultivars may not be as resilient to environmental fluctuations and may not be as hardy.
White’s data makes our pursuit of knowing and growing bee-loving flowers more complex. It is inaccurate to simply say “Echinacea is a great flower for pollinators.” Instead we need to specify which variety. But knowing that natives are generally better for our bees and learning which cultivars feed our pollinators well, can help inform our gardening and provide a truly supportive food source for our bees and pollinators. I look forward to more research done on this topic.