Wednesday, July 28, 2010

Wildflower Wednesday: Bedstraw & Curdled Milk - Updated

As a follow-up to last week’s Fireweed and its horn-tailed muncher, the misnamed Bedstraw Hawk Moth, I thought that this week I’d feature the ignored host: bedstraw (Galium spp.). While Alberta is adorned by several perennial wildflowers in the genus, Galium is probably better known in its weedy annual incarnation: Cleavers (Galium aparine). Cleavers (aka Sticky Willy) is especially pernicious in canola fields because its seed is of similar size to rapeseed and the plants clinging hairs stick to the canola stems and interfere with harvest*.
 Other introduced perennial galia are somewhat weedy, including the attractive yellow-flowered bedstraw G. verum (once used to curdle milk for making cheese – hence Galium from the Greek gala for milk), but one species is usually a welcome addition to a garden: Sweet Woodruff (G. odoratum). Fellow Edmonton garden-blogger The Far North Garden had a good posting on Sweet Woodruff a few weeks ago. She’s having far better luck than I in growing it: in the Home Bug Garden it is just barely hardy – surviving the winter under snow, but loosing out to the freeze-thaw springs.

When it thrives Woodruff makes an attractive ground cover in shady spots. The white flowers are fragrant and the vegetation gives off a pleasant smell when crushed. Coumarins are responsible for the smell, variously described as ‘new-mown hay’, ‘vanilla’, and ‘nauseatingly cloying’** - the latter being how some people react to its use in flavouring German May Wine. Both smelling nice and repelling bugs were the reasons mattresses used to be stuffed with bestraws. Unfortunately, coumarin is a liver poison and a vitamin-K inhibitor, so perhaps the enjoyment of Sweet Woodruff should be limited to smelling, and tasting avoided.
 The crushed leaves of Northern Bedstraw (Galium boreale – sun to shade, Zone 2) have a bit of a new-mown hay smell to them, and were used in mattresses in the Old World (the species is circumpolar), but have smooth stems that do not cling. The tops of the plant are covered with white flowers for several weeks in June and July. My patch is planted in a rather unsightly spot in deep shade and I find it quite attractive in an understated way. I suppose the seeds would get stuck in your socks, but my plant does not set seed – probably because it consists of one self-incompatible clone – so it seems to have no drawbacks and is just tall enough to pop-up at the back of its bed.
 Beetles and small flies are reported as the pollinators of Northern Bedstraw and among the small flies are mosquitoes, some of which are reported to find the flowers highly attractive (Chang 1966, Plant Protection Bulletin of Taiwan 8:50-63). Although acceptable forage to cattle and an important seasonal food source for Prong-horned Antelope (Jacques et al. 2006 Prairie Naturalist Volume: 38: 239-250), levels of insect herbivory to the leaves seems to be fairly low (Agrawal & Kotanen 2003 Ecology Letters 6: 712–715; Agrawal et al. 2005. Ecology 86: 2979-2989). The herbivorous arthropods that I have been able to find records for are all borers and gall formers, e.g. the agromyzid fly Praspedomyza galiivora – described by KA Spencer from nearby Whitemud Creek (Mem. ent. Soc. Can. 64: 1-311, 1969), a couple of gall mites (Phyllocoptes calvus, P. anthobius Liro 1941 Ann Zool Soc Zool Bot Fennicae Vanamo 8: 1-54), and the maggots of the gall midge Ametrodilopsis auripes that forms nodules on the roots of Northern Bedstraw (Tikk & Sil'Vere 1982 Eesti NSV Teaduste Akadeemia Toimetised Bioloogia 31: 150-161).
 Most species of Galium considered native in Alberta have whorls of 4 ‘leaves’ (actually 2 leaves and 2 leaf-like stipules), while the introduced species have whorls of 6-8 leaves. The exception is Sweet-scented or Fragrant Bedstraw (G. triflorum) that has leaves in whorls of 5-6. I haven’t yet seen this forest understory plant in the field, but it looks like it might make a more hardy replacement for Sweet Woodruff as a ground cover for shady spots, although its small greenish to white flowers are much less impressive.

UPDATE - I spent some time watching patches of Galium boreale in flower in the bush this weekend to see what kinds of insects visit the flowers. Visiting flowers isn't the same as pollinating, but it gives a useful first approximation. Over about 20 minutes of checking a half dozen small patches with the close-focussing binoculars I saw mostly tumbling flower beetles (Mordellidae) and small black ants, but also a yellow-faced bee (Hylaeus sp.), a small male ichneumonoid wasp, an even smaller chalcidoid wasp, and three flies (a picture-winged fly [Callopistromyia sp.], either a grass-fly coloured like Thaumatomyia or perhaps a similar-looking agromyzid leaf miner, and a male mosquito).  So, it seems a good variety of tiny insects find the flowers attractive.

*Royer, F & R Dickenson. 1999. Weeds of the Northern US and Canada. The University of Alberta Press. / Lone Pine.

**Small, E. 1997. Culinary herbs. NRC Research Press.

Wednesday, July 21, 2010

Wildflower Wednesday: Fireweed

A recent guest posting at Beetles in the Bush has had me thinking that I should probably write up something about ‘Bad Wild Flowers’ or at least those that are, for one reason or another, a mistake in the home garden. Some charming ‘native’ wild flowers, like Wild Strawberry, go berserk in the garden. Some beautiful wildflowers, like Spreading Dogbane, have somehow gotten on to a list of bad weeds and are not legal to grow. Some seeming wild flowers, e.g. Butter-and-Eggs, actually are invasive introduced weeds. Then there are those native plants with ‘weed’ in their names, like Jewelweed, that loose the jewel and devolve into just plain weeds in the garden. Fireweed (Zones 2-8, sun to part shade, moist soils), however, is one of those native weeds that teeters on the edge of bad, but rarely runs over.

The only real problem with Fireweed - Epilobium [or for some, Chamerion] angustifolium - is that it thrives on disturbance. Wildfires, bomb craters, road cuts, waste areas, volcanic eruptions, and new garden beds are all the same to it – a chance to grow and bloom. Its seeds disperse on the wind and it does a fair job of sending out invasive rhizomes, so it can move with alacrity over long and short distances. However, it is a poor competitor, so established beds are safe, it is fairly easy to weed, the young shoots can be eaten like asparagus (well, if you are starving), and the pith of the older stems is purportedly tasty (although William Cullen in his essential Wildflowers found it more a lesson in the difference between ‘edible’ and ‘palatable’).

Looking over my garden, I see Fireweed where neglect reigns – a monoculture between the garage and the fence, good patches along the driveway and back lane, and here and there a plant or two in a spot, not too shady, where nothing else is thriving. All of these plants descended from a handful of seeds my wife scattered in the Fall of 2003. In a month or less, their descendents will be popping pods and shedding fluffy seeds in humongous quantities, threatening to cover everything downwind in long fine threads. That’s when I will pull out the machete and whack down the stems for the sake of the neighbours’ laundry, barbecues, and piece-of-mind. One neighbour has already mistaken the Fireweed growing through the fence for Purple Loosestrife – which has tall spikes of similarly coloured flowers, but with 6 petals instead of the 4 of Fireweed. A dose of Roundup was avoided by pointing out the difference and that Fireweed is the Floral Emblem of the Yukon, our territorial neighbour to the north.

In contrast to a bit too much vigour and fluff, everything else about Fireweed is spectacularly good for a home bug garden. With enough sun and water one gets 2-3m tall spikes of large pink flowers that bloom most of the summer and are a cornucopia for bees. Bumblebees work the flowers constantly, even during the dreary, cool, and wet days of this Summer. Leaf-cutter bees (Megachile spp.) and Police Car Moths (Gnophaela vermiculata) are equally avid, although more limited by the amount of sunshine. Numerous insects, good and bad, feed on Fireweed vegetation, including a spectacular hornworm – named for some unfathomable reason the Bedstraw Sphinx Moth (Hyles gallii).

Bill Oehlke has a nice webpage devoted to the Bedstraw Sphinx Moth including pictures of the adult. Like most of the sites I have seen, Fireweed, not bedstraw, figures prominently as a food plant for the caterpillars. Since I have two species of bedstraw in my garden, both the European Gallium odoratum and the attractive native Gallium boreale, I thought I’d follow this up. According to the Host Plant Index (Lepidoptera) a Finnish site maintanined by Markku Savela, neither of these bedstraws is listed as a host, but Cleavers (Galium aparine) and the striking Eurasian Galium verum (Lady's or Yellow Bedstraw) are (both are naturalized in Alberta). Fireweed (also Holarctic in distribution) is not listed as a host plant of H. gallii, so perhaps things are different in the Old World. Butterflies and Moths of North America, however, lists bedstraws (Gallium) and woodruffs (Asperula) (both Rubiaceae) and also Epilobium and Godetia (both Onagraceae). Hmm, I bet something very interesting is going on, but I’m not sure what.

While I’m on the subject of host plants, having the Police Car Moth (Gnophaela vermiculata) in the garden isn’t necessarily good news. According to the Strickland Museum species page, Police Car Moths feed on members of the Borage family such as Lungwort (Mertensia paniculata), Puccoon (Lithospermum spp.), and Stickseed (Hackelia spp.). I have not yet tried to naturalize Lungwort in the Home Bug Garden, but I do have lots of Boraginaceae, mostly Borage and Forget-me-nots, but also a Siberian Bluebell (Mertensia sibirica) and a Bethlehem Sage (Pulmonaria saccharata ‘Roy Davidson’) that I am very fond of, and a brand new, expensive Brunnera macrophylla 'Jack Frost' that I would be loathe to see turn into spiny yellow and black caterpillars with red heads. Another conundrum for the Home Bug Gardener? Well, I won’t count my caterpillars before they have hatched and started eating my wallet.

Friday, July 16, 2010

Wildflower [Wednesday]: Blanket Flowers

Not Wednesday, but a rainy Friday and better late than never, the 4th Edition of the garden wildflower series makes its tardy debut. On Tuesday I was in southern Alberta doing field work and enjoying the cold (high 9 C), heavy rain, and gale force winds. On Wednesday, however, things had lightened up enough to snap a few pictures of a garden wildflower in the wild: Gaillardia aristata, the Brown-eyed Susan or Blanket Flower (Zones 2 or 3-9, sun, well drained soil). The genus Gaillardia contains about a dozen species in North America, mostly of limited distribution in the southwestern US, and three species in Argentina. ‘Blanket Flower’ refers to either the colourful blankets woven by some North American Indians or the equally colourful trade blankets sold to them by various entrepreneurs, or perhaps both.
 In gardens, blanket flowers are usually a hybrid (Gaillardia ×grandiflora) between the short-lived perennial G. aristata and the annual Firewheel G. pulchella. Firewheel is native to much of US (and naturalized in eastern Canada), while Blanket Flower extends farther north and west. In the early days of the Home Bug Garden, I planted a few of the hybrid Gaillardia and enjoyed them for one summer. Alas, they followed their annual ancestors (apparent in the ray flowers of ‘Little Boy’) and disappeared over winter. Spring before last, however, I started some seeds of G. aristata from the Devonian Botanical Garden. This year they are blooming vigorously and range from the mostly yellow typical of G. aristata to the red and yellow more typical of G. pulchella, so one suspects some hybridization has occurred among the open-pollinated ancestors in the Garden.
 I hope these more or less natives (the northernmost records for G. aristata in Alberta are just north of Edmonton) managed to hang on for a few years, but I really should start a few seedlings every year if I want to have a steady supply of Blanket Flower. Plants, like animals, have life spans and Blanket Flower is not long-lived. The Edmonton Naturalization Group has a good overview of Blanket Flower and that is what they recommend. Since Blanket Flower has a strong taproot, it does not divide or transplant well, so re-seeding is important to its maintenance. Although sun-loving, my plants have done well in dappled sun and strong competition from a variety of other plants. That Blanket Flower is a good competitor is not surprising – given the strong competition evident in the photo from Dinosaur Provincial Park.
 As well as being of interest in the re-establishment of native prairie and woodland, extracts of the leaves of some species of Gaillardia will inhibit fungal growth and have recently come to the attention of bio-prospectors. More grandly, Blanket Flower adorned the cover of the prominent scientific journal Ecology to highlight research by JC Cahill of the University of Alberta and his colleagues*. Most plants have beneficial fungi (mycorrhizae) that colonize their roots and help them to grow better. In this study, a fungicide was used to disrupt mycorrhizae on the roots of fescue grassland plants at the Kinsella Research Station near Wainwright. JC and his colleagues found that this had a strong effect on the pollinators of the plants' flowers, reducing the number of pollinator visits to the plants with suppressed mycorrhizae and shifting the pollinator community away from the larger bees towards the smaller bees and flies. Blanket Flower was not one of the 6 focal species in the study (yarrow, aster, bellflower, fleabane, goldenrod, and field chickweed), so one assumes it was chosen for the cover of Ecology because of its bright colours.
 One of JC’s students, Tan Bao, is studying Blanket Flower to determine what effect the crab spider Misumena vatia has on pollination. I suppose flowers might very well suffer reduced fitness when colonized by predators of pollinators and one wonders if some plants may not try to discourage such thuggery. For a more romantic picture of this crab spider, check out Adrian’s charming duo at the BugWhisperer.

*JC Cahill, E Elle, GR Smith, and BH Shore. 2008. Disruption of a belowground mutualism alters interactions between plants and their floral visitors. Ecology 89:1791-1801.

Sunday, July 11, 2010

Sawfly Sunday: Double Mystery

I'm between field trips and time is short (and soggy - the weather has not been cooperating), so for this quick and late at night Sunday Sawfly I offer one on its way to being a bird dropping.  For those of us who have seen valued plants becoming sawflies of questionable value, this picture snapped in late August 2007 in a lilac bush in my back yard may offer some cheer. But I offer it as a test - who can identify the bird and, far greater challenge, any guesses on the unfortunate sawfly?

Wednesday, July 7, 2010

Wildflower Wednesday: Bowman's Root Gillenia trifoliata

Bowman’s Root’s current distribution is in the eastern half of North America and it doesn’t seem to have naturalized outside of what is considered its native range. So, although this attractive wildflower is not ‘native’ to Alberta and only Canadian in the sense that it occurs in Ontario (hardly enough justification for some Albertans), I’m giving it the benefit of the doubt. The longer the glaciers stay at bay, the more likely it might have gotten here on its own. Although usually listed as USDA Zones 4-9, my trial planting in 2008 did so well that I added a second plant in 2009. Both are now if full bloom and add a graceful, airy elegance to two shady spots with dappled sun.
 Also called Mountain Indian Physic, Dropwort, Indian Hippo (short for hippocras – a medicinal wine-spice infusion), and sometimes American Ipecac (although this is more commonly applied to the more southern and less ornamental G. stipulata), Bowman’s Root grows to about 60-90 cm (2-3 feet) and does well in partial shade or sun (if the soil is moist) and mildly acid (pH 6.1-9) to neutral soils. Its natural habitat is dry, open deciduous woodlands. I especially like the loose panicles of pinkish white irregularly regular flowers as they wave back and forth on red stems in the slightest breeze. Although Bowman’s Root has a fairly broad distribution, its survival is considered ‘Threatened’ in Michigan, so this is one of those wildflowers one should not remove from the woods. Nor is their any need to since its seeds germinate easily and it is readily available in commercial greenhouses (my plants came from Hole’s).
 Bowman’s Root has been the subject of a fair amount of scientific study, mostly because it has a low haploid chromosome number (n=9) – although related members of the Rose family usually have 17 chromosomes – possibly derived from the doubling of 9 chromosomes and then the loss of one. Thus, something like Bowman’s Root may have been ancestral to a lineage of Rosaceae that now is home to much more famous, if woody and pome-producing, relatives like apples, pears, mountain ash, hawthorn, cotoneaster, and saskatoons. Less seems to be known about the pollinators of Bowman’s Root, but I have found records for the small carpenter bee Ceratina dupla, a couple of mason bees (Osmia albiventris, O. distincta), and a small sweat bee Lasioglossum (Dialictus) imitatum. I’ve seen a small halictid bee, possibly a species of Lasioglossum, pushing its way through the tight basal cluster of petals in my yard. The rather small opening does seem to indicate that the nectar and pollen may be somewhat exclusive, but the Scarlet Malachite Beetle pictured below had no problem forcing its way in.
 As well as having interesting chromosomes, Bowman’s Root was the cause of a minor taxonomic war during the last century. As I understand the casus belli, the name Gillenia was proposed by Moench in 1802 in honour of the 17th Century German Botanist Arnold Gillen. Unfortunately, previously in 1763 another botanist, Adanson, had had the same idea, but for a different plant and proposed the genus Gillena. Unlike zoologists, botanists won’t tolerate names that sound alike but are spelled slightly differently, so in 1894 another botanist (Nathaniel Britton, the famous founder of the New York Botanical Garden) declared Gillenia a homonym and orthographic variant of Gillena and banished it in favour of a replacement genus name: Porteranthus (named for a buddy of his named Porter). However, both names continued in use with Gillenia dominating common usage and Porteranthus the more pedantic side. In the 1990’s a move was made to conserve the name Gillenia (a couple of snippy notes can be found in Taxon if anyone is interested in distilled botanical vitriol) and eventually triumphed because Gillena Adanson was a synonym of Linnaeus’ Clethra (which includes the beautiful North American shrub Clethra alnifolia – which, alas, cannot handle the Alberta winters) and not validly published.
 Bowman’s Root is also part of the American plant pharmacopeia. According to the Plants for A Future Database, the dried, powdered root acts as a cathartic, mild emetic, diaphoretic, expectorant, and tonic. In other words, it makes you head for the bathroom to run at both ends while sweating and coughing up phlegm and, when it is over, you feel better. I think my Bowman’s Root may be looking at me a bit apprehensively at the moment, but they should have no worries. Your roots are safe – I get my tonic from the bark of cinchona trees and with enough gin I usually feel just fine.

Sunday, July 4, 2010

Sawfly Sunday: Cimbex americana Leach

Wildflower Wednesdays and Sawfly Sundays have been on hold the last few weeks because writing lectures and teaching 14 hours a day at the Museum of Biological Diversity in Columbus, Ohio, have taken precedence. The enthusiasm and industry of the 18 students from Columbia, Germany, Canada, Argentina, South Africa, Spain, and the USA have made this course fun, but I do miss the Home Bug Garden. Similar experiments in urban biodiversity are not obvious among the vast expanses of lawn and concrete here. But the old deciduous street trees in some neighbourhoods (complete with defoliating elm leaf beetles) and the occasional sight of some exotic (at least to an Albertan) like a cardinal, black vulture, or Japanese beetle, and one not so exotic and very scruffy ground hog, provided a bit of natural relief. Now I’m trapped at the airport with a cancelled flight and a looming missed connection – but internet – so time for another Sawfly Sunday.
 Cimbex americana Leach is the largest sawfly that I have ever seen and apparently the largest in North America. Named for its predilection for American elm, a once common street tree in the pre-Dutch elm disease era, the elm sawfly also feeds on willows and the leaves of a variety of other hardwood trees. Although Dutch elm has yet to ravage the elms of Edmonton, none grow near the spot we found this large, wasp-like not-wasp: Elk Island National Park. Perhaps this monster is able to fly long distances, but a more reasonable assumption is that its larval stages were spent on some native like the willows that grow so abundantly in the park. The pale caterpillar like grubs have a black dorsal stripe and grow to 5cm (2 inches) in length, so if you have them on your trees, you are likely to notice them.
 Our elm sawfly very obligingly posed for a few pictures in hand before we returned it to a leaf. Many people would probably respond with a bit of fear and loathing to such a large and scary looking ‘wasp’, but this attractive insect has no real way to do more than pinch your finger with its mandibles. The wasp-like show is just that – all show and no sting (but, of course, a saw instead). has a lot of pictures of the adults of this highly ornamented species that seems to mimic different wasps in various parts of its broad range. There are about 15 recognized species in the genus including the intriguingly named Button Horn Sheet Wasp (C. femorata). I wonder how it got that name?