by Laura Gardner, Master Gardener
If you're thinking of creating a pollinator garden with native perennial plants, there will be a period where your space will be rather underwhelming or undeveloped.
There is a saying, "first year they sleep, second year they creep, and third year they leap." In the first year of their growth, many native plants focus channeling their energy into root development instead of flowering. It is important to consider other ways to increase floral resources for pollinators while you wait for these plants to grow.
Consider adding a few native species that are short-lived annuals or biennials—either potted plants or directly sown seed. If started early in the spring, Black-Eyed Susan (Rudbeckia hirta), for example, will bloom in the first year. It usually produces enough seed to ensure future generations.
Spotted Horsemint (Monarda punctata) and Lanceleaf Coreopsis (Coreopsis lanceolata) are a couple of others that will also bloom the first year when started early. Near-native annual sunflowers (Helianthus annuus) are another great choice for new pollinator gardens. An important consideration for choosing annual sunflowers is to make sure that they are not pollenless types.
That said, there really are not a whole lot of native annual species that you can add. To help fill in the gap, it is possible to consider some non-native annuals. An aspect of this that is concerning is whether these plants provide adequate nectar and/or pollen to pollinators.
Many annuals have been bred for size, colour, vigour, and length of bloom period and not so much for their nectar and pollen production. When I visit a garden centre, I pay attention to see if there are any insects visiting the plants. I usually don't see a whole lot of activity. Of course, this is anecdotal, so what does the research say?
From my cursory reading, the research is a bit uneven. A UK study in 2017 found that most ornamental flowering plants found in garden centres were unattractive to pollinators.[i]
Another US study that looked at a select group of annuals found that while native plants were superior overall, there were some non-native annuals that could be important forage for pollinators. It was found that in comparison with Zinnia, Marigold (Tagetes), Lantana, and Starcluster (Pentas), Sweet Alyssum (Lobularia maritima) was the top performer. In particular, the cultivars "Frosty Knight" and "Snow Princess" showed the greatest diversity and abundance of pollinators compared to the other Lobularia types as well as the other species.[ii]
This year I planted some Lobularia near my vegetable garden in the hopes of attracting beneficial parasitic wasps. The adult wasps will seek out the nectar from the flowers and look for caterpillars on my Brassicas for their young.
Another more recent study from June of this year also found that while the native plants in the study were visited more by pollinators than the non-native plants, there were still some desirable non-native annuals. Specifically, Begonia and Impatiens were visited more frequently by pollinators than Pansy, Petunia, New Guinea Impatiens, and Geranium.
Similar to the previously mentioned study, these researchers found that there was variability between cultivars of a species. Of the cultivars, the four most visited were Begonia 'Cocktail Brandy', Begonia 'Ambassador Rose Blush', Impatiens 'Accent Coral', and Impatiens 'Super Elfin XP White.'[iii]
Now, an important question that comes out of this is whether these plants provide quality floral resources for pollinators. Pollinator visits to flowers does not necessarily mean that they are benefiting from the resource. More research is needed in this area. Until then, we can make a few reasonable annual plant choices to help in the interim while the other plants in our new pollinator gardens mature.
[i] Garbuzov, Mihail & Alton, Karin & Ratnieks, Francis. (2017). Most ornamental plants on sale in garden centres are unattractive to flower-visiting insects. PeerJ. 5. e3066. 10.7717/peerj.3066.
[ii] E Erickson, S Adam, L Russo, V Wojcik, H M Patch, C M Grozinger, More Than Meets the Eye? The Role of Annual Ornamental Flowers in Supporting Pollinators, Environmental Entomology, Volume 49, Issue 1, February 2020, Pages 178–188, https://doi.org/10.1093/ee/nvz133
[iii] David Smitley, Colin Oneil, Erica Hotchkiss, Erik Runkle, Jared Studyvin, Evaluation of the most popular annual flowers sold in the United States and Europe indicates low visitation rates by pollinators and large variation among cultivars, Journal of Economic Entomology, Volume 117, Issue 3, June 2024, Pages 1057–1070, https://doi.org/10.1093/jee/toae084
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