Saturday, March 19, 2016

Floral Visitors 18

Muscari armeniacum with a honeybee
Pollinators of all kinds have been out, particularly bees who are taking advantage of the introduced species in my garden. Muscari is in full bloom, attracting gangs of honeybees. Last year I witnessed a variety of other floral visitors such as plume moths (Pterophoridae), geometrid moths (Geometridae), anthephorine bees (tribe Anthophorini), and other small arthropods. They don't seem to increase very well here, perhaps the soil is not to their liking or it dries up too quickly after the Spring rains cease. Most of them are planted out in native soil, rather than a raised bed where I grow most of my perennials. Perhaps they would benefit from a fall application of leaves to encourage some microbial activity (thus stimulating quicker nutrient cycling).

Scilla siberica
The bulbs of Scilla are sometimes considered to be irritating when handled by some people, and my assumption was that the assumed irritating constituents would also deter animal pests. Deer surely ignore them, yet voles are seemingly unaffected. Last year, I had a lot of Scilla siberica planted around and it had been a reliable resource for honeybees and bumblebees. However, this year has seen a drop in the number of flowering plants and honeybees have not been observed visiting them. Still, this wont keep me from attempting to grow more, next time I'll just use mesh baskets or wire cages, a necessary pain in the a**.

Chionodoxa luciliae (syn. Scilla luciliae)
The Chionodoxa, now widely accepted as Scilla, are like S. siberica and now are few in the garden. Yet, these tiny blue flowered bulbs have swooned me and I will continue to plant them into the garden, next time with underground protection. The pollen of Chionodoxa is not as exposed as Scilla, perhaps an adaptation to prevent damage or loss of the pollen from rain. It may just be a coincidence, but it seems bees are less interested in Chionodoxa than Scilla (sensu stricto) which have highly available pollen and nectar. Bumblebees were spotted visiting Chionodoxa last year, perhaps because they possess probosces that are robust enough to push between the anthers to reach the nectaries within.

Hyacinthus orientalis with Mecaphesa, a bee predator.
Hyacinthus, the common hyacinths sold alongside tulips and daffodils in the fall, are highly attractive to honeybees even when planted in small quantities, unlike the other scillas. I have a handful of hyacinths planted under a native wild lilac, aka deerbrush (Ceanothus integerrimus). Ceanothus are good for beneficial soil dwelling microbes, and are known to fix nitrogen, a result of a symbiotic relationship with some type of soil dwelling fungi. The plant trades something (root exudates), and in return receives nutrients or something similarly useful from the fungi. This in turn benefits everything growing in the vicinity because nutrients that would otherwise be unavailable to plants for one reason or another are being made continuously available by microbial activity. Hyacinthus orientalis are known to be heavy feeders, and will dwindle over time in less than adequate soil. Yet here under the Ceanothus, they are thriving! (Learn more about nutrient cycling here.)

Anemone blanda
Similar to the Hyacinthus, Anemone blanda is similarly attractive to honeybees even though there are relatively few of them and they are not planted near each other. Unlike hyacinths, the main appeal here is for the pollen. Besides honeybees, a variety of bumblebees and flies (Syrphidae, probably other families too) also visit these flowers. It is uncertain as to whether or not they produce nectar, or if they do it may be in a very small quantity and highly dependent on the growing conditions (including aspect). In general, when plants are grown in less than optimal conditions, the first thing they'll do is cease nectar production, survival comes first. Pollen, however, is much more important to a plant since it is required to create the next generation of plants. Pollen is also highly important to bees this time of year because it is the sole source of protein for developing larvae, nectar and honey being reserved for adults who require high amounts of carbohydrates to fuel flight and other tasks important to survival. (A fun/appetizing fact: wasps utilize other insects as the protein source for their larvae instead of pollen. Bees are basically vegans while wasps are largely predators/carnivores, though the adults of both feed on nectar.)

Hepatica acutiloba
Closely related to the genus Anemone, and often considered to be included in it, the single Hepatica in my shade garden attracts few to no pollinators. Though beautiful, it has some factors working against it when it comes to pollinator attraction. First, it is grown in shade while bees prefer to work flowers in the sun, especially this early in the year when the days are still very cool. Second, there is only one. A single flower of any plant is highly unlikely to attract anything, except for a photographer. Bees and other pollinators are more attracted to groups of plants (Xerxes Society studies suggest single species plantings of 3×3' or larger to be most effective), and are most attracted to groups of single species rather than mixes. However, I do find that having a mix of flowers does attract a wide range of pollinators nonetheless. I do plan on acquiring more Hepatica for my shade garden, as well as more flowering plants for my shade garden to entice more pollinators into the dark.

Crocus vernus
A lone Crocus stands under Pinus ponderosa, where dozens of other crocuses were planted and many were uprooted by both deer and turkeys. As the year progresses, fewer and fewer crocuses are to be seen and fewer and fewer are likely to be visited by pollinators in my garden. This is probably due to the increase in competition and the decrease in the population of the crocuses rather than their general appeal. I strongly believe that if I had a field of the latest blooming Crocus they would be crawling with pollinators (and probably also filled with deer, voles, turkeys, and other herbivores). This is probably the last look at Crocus for the year, unless my saffron decided to bloom this year.

Viola odorata and Vinca minor
I have worked hard to build up a thriving community of plants in the small raised bed around my well house, and the work has paid off. Vinca minor, a close relative to the highly invasive Vinca major (which coats entire riparian banks and shady hillsides that are too dark for Rubus armeniacum), grows happily along with dozens of other small plants. Much of what grows here now was sown as seed, some planted as offsets. Roots from nearby Pseudotsuga menziesii invaded these beds quickly after they were established, and brought with them myriads of fungal hyphae. At first I thought this was a horrible thing, and I had attempted to eradicate the beds of the intruders, a futile task since there is a 100' tree less than ten feet away. Now I see that the plants growing there now have no issue competing with the tree roots, and I hypothesize that the fungal network has brought with it a diversity of other microbes which are supporting the growth of the plants.

Microbes sequester nutrients which could otherwise be lost due to watering or rain and delve deep out of the reach of plant roots. These nutrients are eaten by microbes, sequestered in their bodies, and released when the microbes either die of natural causes or are eaten by other microbes, thus making them continuously available to plant roots. So a diversity of microbes is a good thing. The microbes are supported by a diversity of plants, all of which release different exudates (the closest thing to plant poop) into the rhizosphere (the area just around the roots) and feeding the microbes. Many microbes occupying the rhizosphere feeding on exudates can crowd out pathogenic microbes and prevent disease in plants. The benefits go on and on.

Now back to Vinca, they are reportedly bee pollinated, though I have made no such observation. The blue flowers are nice though, and with all of the competition I doubt the plant will get too out of hand.

Viola odorata
Sweet violets are very satisfying to me. They grow very well here, require no Summer irrigation (though they flower better with it), and are happy in sun or shade. Bees appreciate the flowers, and where they are prevalent can be detected from afar by their sweet scent. They also like to spread, so it is worth taking the time to consider their placement before introducing them to your garden. If you have a lawn or a large patch of bare ground, say, under a tree, they'd be perfect! They don't require pollination to set seed, and will spread by runners, so a sizable patch may be formed in a short period of time.

Lamium maculatum
Another very easy plant that is attractive to bees, Lamium maculatum grows in the sunny corners of the raised beds surrounding my well house. It is a low growing maintenance-free creeper that can tolerate a lot of drought when established, is ignored by deer, and unaffected by mole/vole tunneling. Bumblebees are most interested in the odd reptilian-reminiscent flowers, though honeybees will occasionally frequent them.

Further Reading:

Lee-Mäder, Eric, and Marla Spivak, eds. Attracting Native Pollinators: Protecting North America's Bees and Butterflies: The Xerces Society Guide. North Adams, MA: Storey Pub., 2011. Print.

Walker, Travis S. et al. "Root Exudation and Rhizosphere Biology". Plant Physiol. Vol. 132, 2003.


  1. if you do see any Vinca minors with honey bees please let me know - i heard they were not good for bees but have some shade the plants would like. Great photos as always, i so enjoy your info, thank you!

    1. Will do! I will say that I doubt they will be of consequence unless there were a lot more of them. I'd recommend something in the Boraginaceae: Comfrey, Omphalodes, Trachystemon... But those can be a bit aggressive. Pulmonaria loves shade, and is not aggressive.


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