Of Spring Beauties and Lesser Celandines

A few spring beauties surrounded by the invasive lesser celandine

Lesser celandine along the trail where native flowers used to be

Last year I was disheartened to find that the lesser celandine, that attractive but aggressive invader, had spread over the land that once belonged to spring beauties and trout lilies. I am sorry to say that it looks like the non-native continues to make inroads.

Pachysandra, upper right corner; snow drops, bottom; spring beauties, center; lesser celandine. There are also stems of another alien, multiflora rose

Lesser celandines, with the help of snow drops and pachysandra, all of them garden escapees, have taken over the forest floor along my favorite nature trail. Later on, garlic mustard will show up in all the same places, but now it is not in sight. Snow drops were in bloom the last couple of weeks and now they are past their prime. This is another delightful but aggressive invader which brings joy to the hearts of many with its early blooms. Spring beauties struggle to survive hemmed in by all these newcomers to the land. Trout lilies face the same predicament in these areas.

A patch of lesser celandine

This spring I want to see how our native spring beauties and their pollinators are faring among the many introduced plants. So a few days ago I sat on my little stool on front of a patch of lesser celandine. It was a warm and sunny day and insects were quite active, including some gnats that enjoyed attacking my ears and forehead. During my forty minutes of observation I saw a number of little dark insects approach the patch and inspect the blooms by briskly hovering above them. Only one landed on a flower and stayed long enough for me to recognize it as an Andrena bee, the kind that would be loading her leg baskets with pollen from spring beauties if there were any around. Soon it left without attempting to gather anything from the flower. Perhaps it was just using it as a perch to pause during an exhausting and frustrating search for its favorite food.

Another patch of lesser celandine, near a stream

I continued my observations two days later. For more than an hour I walked along the trail illustrated above. I kept my eyes open for flower visitors and made frequent stops. I found only a handful of spring beauties nearly smothered by the lesser celandines. Even that very low number managed to have a few visiting bees. On the other hand, the bright yellow blossoms of lesser celandine remained neglected by anybody other than a small gnat and a beetle.

Finally, I sat for half an hour on front of another patch of lesser celandine, as on the previous time and intently looked for flower visitors. Finally a honey bee showed up and methodically worked the flowers. Let us remember that both honey bees and lesser celandines are European imports. There were no native pollinators in sight.

I should be glad that the lesser celandines don't get pollinated; but I can't. The variety brought from Europe propagates primarily by small bulbs (bulbils) with no need for pollinators. It reproduces this way only too well. Its abundance and the growing scarcity of spring beauty flowers forces the Andrena bees to travel longer and longer distances to gather pollen for their young. As a result, they can raise fewer and fewer babies each year. Both the flower and its pollinator continue to lose ground to the invaders.

A spring beauty and its pollinator, a rarer sight each year

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Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2012

Where have all the spring beauties gone?

We are studying the pollination of spring beauties. The main pollinator of this lovely early spring wildflower is a bee, called the spring beauty bee (naturally). It is a species of Andrena, small, black and slender. Like all other Andrena, it has characteristic hairy spots between the eyes. This pollinator may visit other spring flowers for nectar, but it is thought that it only gathers pollen from spring beauties. To learn more about this bee, its geographic distribution, populations and its role in ecosystems, a number of volunteers throughout the eastern United States are collecting data of its visits to spring beauties.

So, I started prospecting my favorite spots where I had found these little gems of the woods floor in previous years. I was frustrated to find lesser celandines instead. I kept walking the familiar trail, and the scene was always the same: extensive carpets of glossy dark green leaves and vibrant yellow flowers. Only here and there did I see a sprinkling of spring beauties, fresh leaves of trout lilies and a few other early flowering plants of the woods.
I must say that lesser celandines are really beautiful. No wonder why they were brought to this country as ornamentals! And no wonder why many garden centers sell them and gardeners buy them! The sinister side of this invasive beauty doesn’t seem to register in the minds of commercial centers and uninformed gardeners. But conservationists see something else. Lesser celandine is replacing some of the native plants, creating a cascade effect on the balance of nature. Native plants feed native pollinators and many other insects, which in turn, benefit other members of the natural community.



I turned my attention to lesser celandines: Do they get any visits by pollinators? Do they provide any services to the natural community?
I sat down for hours on a small picnic stool surrounded by blooming lesser celandines, camera in hand, ready to snap pictures of pollinators; hardly any came. I will continue to observe lesser celandines, but I fear that I already know the answer: specialist pollinators, such as the spring beauty bee or the trout lily bee are not likely to visit these invaders of forest and gardens, useless to them. I know that in their native land lesser celandines are visited by mutually adapted pollinators and that they provide food to some caterpillars (which in turn feed birds), but nobody seems to find them nutritious in this country.
Alarmingly, this plant is a very successful invader, with means to spread by bulbs and with the ability to sprout so early in the spring that it has a head start over the other plants in the forest. Thus a rent appears in the web of life. The more this successful invasive keeps spreading, the larger the rent becomes.

Update, April 28: Fortunately I have been seeing lots of spring beauties in other places. Let us hope that lesser celandines don't spread there too.

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© Beatriz Moisset. 2012