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.