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.

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