When deadheading flowers, leave stems about 18″ long; in other words, don’t cut them down you the ground. Many bees can use them for as nesting sites. They will lay an egg in the stem and then pack it with food, plugging it with grass or mud. Bees will also tunnel out stems like elderberry or, as in this case, Penstemon. Now, I know you are thinking, “But I don’t want ugly dead sticks in my garden”. Plants, like this Delphinium, will grow up around last year’s stems, concealing them with foliage and beautiful blooms.
Stem pith from bee tunneling, Penstemon ‘Husker red
Plugged bamboo nests, Bee Research Lab
Delphinium stems left for stem nesting bees. New foliage and flowers grow up to conceal old stems.
Annual flowers change throughout the season. At the Flowers for Pollinators St. Paul site, some flowers have been quite slow to flush out a decent bloom (cosmos, white swan sage, lemon queen sunflowers, Rudbeckias, Twizzle Penstemon) while others were amazing right away and now look, well, pretty lousy. The sunflowers which I was so blown away by are being decapitated by a weevil.
Sunflowers I deadheaded are struggling to flush out a weak second bloom. The Popart zinnias continue to be resilient and bloom well though are a bit ragged. Some that are still looking great are the butter daisy (Melampodium) which continues to look almost fake it’s so nice, the short marigolds, the orange fudge Rudbeckia, Dakota Gold, and Zinnia ‘Old Mexico’ (one of my personal favorites) and Zinnia ‘Zahara Starlight Rose’. Click on pictures for captions.
Still looking good: butter daisy (Melampodium)
Slow to bloom, but on top now: Orange fudge Rudbeckia and Cosmosnd Cosmos
Zinnia ‘Zahara Starlight Rose’
My fave Old Mexico Zinnia
So how does this late season effort reflect on pollinator activity? Fewer sunflowers have resulted in insects visiting other plants. For example, there was little to no activity on the butter daisy until the sunflowers bit the dust. This could be due to the fact bees are opportunists and efficient pollinators. They will stay with one flower until they are finished collecting the pollen. This is great for the flowers as compatible pollen is important to reproduction.
The honeybees are still the most widely seen insects in the garden (if you ignore the rash of Japanese beetles. Hoo boy.). Bumble bees have been almost nonexistent here at the St. Paul site and I am not sure why as we saw them often on the same Salvia varieties last year in a garden not far from this planting site. Hover flies, too, are less frequent as well. Does the age of the flower have anything to do with it? Could the presence of other insects like the Japanese beetles? Other insects are coming onto the scene now – soldier beetles, stinkbugs, assassin bugs and gorgeous butterflies. Click on the pictures for captions.
Soldier beetle on Orange fudge Rudbeckia
Assassin bug finished with honeybee
Wow! Swallowtail on Popart red and white Zinnia
It is fun to see the Morris F4P study garden – and visitors to the annual Horticulture Night in the Display garden were intrigued by the flowers. Many loved the Suntastic Bicolor Pink sunflower, and I saw a lot of people jotting down names and taking pictures on their phone. There was some visible deer damage, and a bunny was the focus of three toddlers, but made me nervous hiding in the Rudbeckia. Several people took the survey, but most wanted to just admire and plan their next annual garden. Thanks Joe Knight and Steve Poppe for taking care of the Morris F4P planting!
I stepped out of my office late this afternoon into the wicked heat wave to check the plants in the St. Paul Display garden. I am worried the Japanese beetles will find our zinnias (not yet – they are still absorbed in the plum tree, grape vines and milkweed flowers). While watering, I observed that, in spite of the 96 degree heat index, honey bees were active visiting almost all the flowers – even those not previously where activity hadn’t been seen to-date. I am curious why bumble bees – so active last year – have not been seen much this year. Will keep watching.
Though advertised as pollen-less, bees are still finding this sunflower irresistible. Perhaps there are nectar rewards. I watched the bee for quite a while to see if it stopped for a “big gulp”, but it seemed to just be searching and hoping to find.
Visitors to the St. Paul campus will find the Flowers for Pollinators garden in the Horticultural Science Display Garden at Gortner and Folwell avenues. Stop by throughout the summer and observe the interactions of pollinators and plants. Be part of the study by recording your observations on a survey.
2017 Plant List