A reminder: don't forget the pollen

This month I’m inadvertently demonstrating a point about nonnatives and double flowers. I bought some plants for their flower color, and the result reminds me to stick to my new selection priorities.

    Three weeks ago I realized that some of my container plantings were looking sad and could use an upgrade. Two were filled with variegated foliage of Swedish ivy (Plectranthus coleoides) for a shady spot near the front steps. After three months, the plants had grown large, but I was finding them boring. Meanwhile, in a pot on the back deck, a color clash had developed between two zinnias, one with sunflower-yellow flowers and the other salmon pink. I moved the yellow-flowered plant to the insectary bed.

Bees like it, but the color didn't work for me

    Then inspiration struck. I remembered that when local garden centers put out fall chrysanthemums, they’re usually accompanied by some asters loaded with buds and ready to bloom. A pink-flowered aster could add pizzazz to all three of these pots. Plants already covered in buds would bloom whether they got a lot of sun or not.

There might be some asters among the chrysanthemums-photo Elvert Barnes

    I went to my favorite neonic-free garden center looking for pink flowers. I seized on the only pink aster on offer, probably a Chinese aster (Callistephus chinensis). The plentiful buds hadn’t opened yet, but the label said they’d be pink. I brought three plants home and popped them into the pots that needed more zip.

    Now that the flowers have opened, I’d call the color magenta, not pink. The new asters brighten the pots, but they aren’t offering forage for pollinators the way I’d hoped they would. It’s especially obvious in the backyard. A few feet from the new blooms, the blue flowers of a single New England aster are drawing dozens of bumblebees. 

This single-flowered native aster draws lots of bees

The pompom flowers of the new plant just sit there in solitary, sterile splendor. That used to be fine with me, but it doesn’t mesh with my recent focus on supporting a diverse population of insects, especially pollinators.

Sparse pickings for pollinators

    I think there are two reasons that the new asters aren’t getting any visitors. First, they’re nonnatives, so they don’t offer pollen that native insects need. Second, the flowers are double. They have more petals than the nearby blue aster flowers but hardly any yellow central disk. They have little nectar for visiting insects. When growers breed plants for double flowers, the pollen-carrying stamens are often replaced by extra petals. Although the resulting flowers look fuller, they don’t do anything for pollinators. Better choices would have been single pink New England asters such as ‘Alma Potschke’ or ‘Harrington’s Pink’.

There are nice single-flowered pink asters out there

    One of the reasons I flubbed this flower choice is that there are so few local garden centers reliably offering plants that haven’t been treated with pollinator-killing neonicotinoid insecticides. I hope that by next fall more of the area’s garden centers will have announced that they’re neonic-free. Then the pollinators and I will have more options.

    The sustainable gardening course I’m offering in my yard is coming up soon, Saturdays October 26 and November 2. Check out the catalogue listing here through Newton Community Education.