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Friday, December 3, 2010

Symmetry


I am looking at a picture I took several years ago of a bee visiting a sunflower. The head and front part of her body are metallic green. The last part, the abdomen, is striped black and white. A very striking little bee, a jewel contrasting with the golden yellow of the flower. She carries two enormous baskets loaded with pollen on her hind legs. These ingenious organs resembling grocery baskets are made of abundant longish feathery hairs that hold the loose pollen grains. She keeps working the little florets at the center of the flower in search of additional pollen and some nectar to carry home for her children. These bees can be quite abundant in suburban gardens but often go unnoticed by human visitors; their role in the garden remains mysterious and irrelevant to the gardener, no matter how conscientious he or she is about the needs of the plants. These bees are so unknown to most of us that they haven’t even earned a common name. Scientists refer to them by the intimidating name of Agapostemon virescens. I wish I could tell you what Agapostemon means; all I can say is that virescens refers to their green color.

I notice in my collection another picture of a bee on a sunflower. It looks like a mirror image of the first; same colors, same posture, same heavy load of pollen. Except that this picture was taken four years later. It isn’t the same bee, not even a sister; more likely it is the great-great-granddaughter of the first. I delight on the symmetry of these far removed generations. Life goes on in the wildflower patch. I wonder if the flower is also the great-great-grandchild of the first one. It is possible. Symmetry of a different dimension: the flower nourishing the bee and her brood so she can carry on year after year and the bee ensuring that the plant can make seeds and reproduce. Two distinct threads of life intertwined for eons.


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© Beatriz Moisset. 2011

Sunday, October 10, 2010

Lawn for Pollinators. Part III


As mentioned many times before, it is preferable to have a wildflower meadow than a large expanse of lawn; however, some areas need to be mowed to allow walking on them or to enhance the garden. Grass companions, plants that are good to pollinators and to wildlife in general are welcome in such areas. They are healthy for the lawn, can be quite pleasant to look at and can provide food for many types of wildlife including bees, butterflies and birds.


One grass companion that is good in the fall is the aster, or several species of asters. Their pretty, daisy like flowers add a sparkle to the uninterrupted greenness. The genus Aster is rich in species; some of them are so similar that even botanists have trouble telling them apart. Many are used in wildflower gardens and wildflower meadows; they can be too tall to become part of a lawn; a few manage to escape the meadow and survive repeated mowings, growing very low and close to the ground. Thus they become grass companions.


Here is a field where asters are interspersed with the grass; if mowing isn’t too frequent they manage to grow several inches tall and to produce many flowers in September and October. If the lawn receives more frequent mowings the plants hug the ground and still produce a pleasant array of little flowers. Finally if the lawn is mowed closer to the ground and with higher frequency the asters may fail to bloom, but they still provide a nice ground cover, green, thick and supple.

Such flowers don’t fail to attract a considerable number of pollinators; I see them in abundance when I walk through a field where asters are accepted as part of the lawn. Skippers are very common visitors; other flashier butterflies, such as fritillaries and buckeyes, also show up.



A variety of Syrphid flies or hover flies come to visit the aster blooms. They may not be very efficient pollinators but they perform another very important function: their babies devour aphids; so they are welcome visitors in any garden.


Finally, some of the most important pollinators come to the asters: many sorts of bees, among them the beleaguered honey bees, several types of bumble bees and a few other native bees of the solitary type.





Update, 2013: Many species of native asters are now in the genus Symphyotrichum.

Lawn for pollinators. Part I
Lawn for pollinators. II

List of articles

© Beatriz Moisset. 2012

Sunday, September 19, 2010

Jack-in-the-pulpit and its cruel deception


Early in the spring you can often see Jack-in-the-pulpits in your walks through the forest. The peculiar shape of its flowers gives it its name, a big leaf, the spathe, makes up the pulpit and a rod inside, the spadix, is the person. It is the spadix that carries the minute and numerous flowers; some plants have only masculine flowers inside the pulpit and others have only female flowers. How are they pollinated? They don’t have flashy colors nor perfume, they are not placed in a prominent place like most flowers but they are close to the ground and hidden beneath the leaves. So what kind of insects do they attract? The jack-in-the-pulpit belongs in the same family as the calla lily and the skunk cabbage, this family is notorious for using all kind of ruses to attract pollinators without giving them any reward and Jack-in-the-pulpit is no exception.


Apparently the flower of Jack-in-the-pulpit smells somewhat like mushrooms and attracts fungus gnats. The insects fall inside the pulpit and if it is a male flower they get covered with pollen in their effort to escape. The sides are so slippery that they can’t climb up and keep falling back to the bottom, fortunately there is a small hole at the base of the pulpit and they eventually find their way out; they leave the place no worse for the wear, although probably somewhat mortified by their mistake. They don’t seem to learn their lesson and keep on venturing inside other Jack-in-the-pulpit flowers. If they fall into a female flower they leave their load of pollen on it, but in this case they cannot escape, there is no opening at the base. Every maturing fruit of a Jack-in-the-pulpit contains one or several entombed gnats wrapped by the dried up spathe. That is how this plant repays its pollinators, a cruel deception indeed!


   
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Jack-in-the-pulpit

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© Beatriz Moisset. 2012

Saturday, April 24, 2010

Lawn for Pollinators. Part II

Winterthur in the Brandywine Valley near Philadelphia. Large expanses of lawn such as these are being turned into meadows with paths rambling through them.

We have covered an astronomical number of square miles with lawns, lawns that are in most cases deserts, useless to wildlife. That surface is comparable to that of Pennsylvania, New Jersey, Delaware, Maryland and Rhode Island combined.

If you live in the West you may prefer to see this surface as equivalent to that of the state of Washington.

Do we need that much lawn? Much of it could be turned to meadows or other plantings according to the mantra: "Less lawn, less mowing, less pollutants, more natives". This is being done in places such as the New River Gorge National Park Visitors Center in West Virginia. The meadows and grassy paths are pleasant to the eye, beneficial to wildlife and healthier for everybody.

New River Gorge Bridge Visitor Center. WV

Lawn for pollinators. Part I
Lawns for pollinators. Part III

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© Beatriz Moisset. 2012

Sunday, April 4, 2010

Lawn for Pollinators. Grass Companions

Yellow violet
Ordinarily a lawn is a desert, very unwelcoming to wildlife from tiny insects to birds. It doesn't have to be this way. A lawn can supply food for pollinators and even for birds; it can also provide housing for some pollinators.

We can make our lawns more nature-friendly by readjusting our notions of aesthetics: a perfectly manicured lawn that looks like an indoor green carpet need not be the only ideal of lawn beauty. Instead, a lawn with some variety of plants which includes a few broad-leaved “weeds” has its own kind of natural beauty; let us call them “grass companions.”

The very first step, naturally, is to avoid insecticides and herbicides whenever possible. The choice of broad-leaved small plants that you can allow in your lawn is a little trickier and it may take some time to get the right combination; but the final product would be a pleasant lawn that requires less care and less fertilizing, providing more resilience to droughts and pests in addition to being more hospitable to desirable wildlife. There are a number of little flowering plants that grow in lawns completely uninvited that we are constantly trying to eradicate; however we could start welcoming some of them.

Ideally, you want only non-invasive lawn flowers, preferably native ones, but this would require effort beyond that which many gardener would be willing to invest. So it is understandable when gardeners accept some non-natives; after all most lawns are made up of grasses which may not be native to your region.

Some of my favorite grass companions, such as violets, bluets and spring beauties do well only where foot traffic is minimal, or where mowing is less frequent. Others can take a good amount of abuse:

Bluets
• Blue eyed grasses (Sisyrinchium, several species) not a true grass but a member of the iris family, with pretty blue flowers.
• Cinquefoils, (Potentilla).
• Wild strawberries (Fragaria, several species). The five lobed leaves of this and those of cinquefoils are very similar in appearance.
• Yellow violets (Viola pennsylvanica), and other kinds of violets too.
• Spring beauties (Claytonia)
• Wild geraniums, crane’s-bills (Geranium)
• Azure bluets (Houstonia caerulea).
• Speedwells (Veronica), there are several species, some of them are native others introduced.
• Wood sorrel (Oxalis acetosella), used as ground cover by some gardeners.
• Chickweeds include two genera: Cerastium and Stellaria. They are also known by several other common names; some species are native and small enough to do well in lawns, such as field chickweed, (Cerastium arvense) and star chickweed (Stellaria pubera).
• Smartweeds, knotweeds, many species in the genus Polygonum; some are small enough to do well in lawns. Some species are native and others introduced.
Asters (Symphyotrichum) are great in the fall. Some grow rather tall, better for a meadow than a lawn; but if mowed not too frequently, they can do well and bloom heavily inviting many species of pollinators.

Among the non-natives, a very useful one is clover, (white clover, Trifolium repens) a European plant very well established in the United States; it used to be included in grass seed mixes because it helps fix nitrogen, enriching the soil as a consequence. There are a few species of clover that are native to some regions of North America. Chickweeds, also known as starweed, bindweed, winterweed, as mentioned above some are native others aren’t; the seeds of some are eaten by some birds, hence the name chickweed. Gill over the ground, or ground ivy (Glechoma hederacea), is rather pretty but it can be very invasive. Thyme, (Thymus several species) has been used as ground cover sometimes. Scarlet pimpernel, (Anagalis arvensis) a European plant with small pink flowers. Dandelion (Taraxacum officinale) is among the non-native invasives which you may not want to see around. Some think that it doesn't provide much of anything to pollinators despite its colorful flowers, others fear that it may compete for pollinators with some native flowers, reducing their pollination.

Chickweed
These are just a few of the "grass companions" that do well in my region, the Mid Atlantic. Other areas might use some of the same along with other “companions” based on regional conditions.

A simple practice that can be helpful to pollinators in your lawn is to allow some bare spots in dry and sunny places that can be used for nesting by bees and some insect eating wasps. Some leaf litter, especially on or near flower beds, can provide shelter for fritillary caterpillars and hummingbird moth caterpillars and a few other wintering moths and butterflies.
Asters

Lawn for pollinators, part II
Lawn for pollinators, part III

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2010