When summer fields are full of tall bright red flowers, you can be sure you’re looking at a sea of Paintbrush (Castilleja). There are about 200 species of this flower. They can be found from the Andes through Central and North America, through western Eurasia and northeast Russia.
Many species, many colours
There is a persistent notion that the various colours of Castilleja “flowers” (actually, the leafy bracts that surround the narrow, green flowers) occur due to variations in soil chemistry. However, the amazing range of paintbrush colours seen in Alberta is actually from the fact that we have a dozen distinct Castilleja species. Several of these vary in colour themselves. Plus, experts tell us that in certain areas, the species can also cross with each other to produce “hybrid swarms” (pictured below). These are plants intermediate in characteristics between the parent species. They can produce the most amazing colour combinations!
The most common species here is the Giant Red Paintbrush, Castilleja miniata, pictured above, which ranges from western Mexico, through the western U.S. and north to Alaska In K-Country. It’s found from lower elevation grasslands up into the alpine.
Through those lower elevation grasslands, you might find Stiff Yellow Paintbrush (Castilleja lutescens, pictured at left), though it’s more common to the east and south. Venturing into the subalpine and alpine areas, you’ll see showy tracts of Paintbrush with beautiful pink or purple bracts. This is Rhexia-leaf Paintbrush (Castilleja rhexiifolia, pictured below right).
Alpine meadows and ridges are also home to tiny Western Alpine Yellow Paintbrush (Castilleja occidentalis, below left). Its bracts are typically cream-to-yellow, sometimes with reddish bases. The whole plant is usually under 15 cm in our area.
Red coloured Paintbrush are the primary food for hummingbirds in this area. Some research suggests the hummingbirds and Paintbrush co-evolved. These flowers have almost no scent (hummingbirds are attracted to red colours, not aroma). They also have a long deep flower that hides its nectar. The tough flowers can withstand hummingbird bill stabs.
And they’re parasitic
The genus, Castilleja, belongs to a group of plants called “hemiparasites”. Like most other plants, Castilleja leaves and stems contain chlorophyll which is what gives them their green colouration. Chlorophyll absorbs light and is key to the process of photosynthesis. This is the means by which most plants convert energy from sunlight, carbon dioxide from the air, and water from the soil, into nutritious sugars.
However, hemiparasites also steal a bit of resources from the other plants they grow with. They do this by sending out specialized roots (haustoria) that tap into the root systems of other nearby plants. While this may sound like a damaging thing, casual observers would be hard-pressed to notice any difference in plant growth between areas with Castilleja (or other hemiparasites, such as lousewort or yellow rattle) and those without. And it should also be noted that hemiparasites do not kill their host plants. They just divert a little of the host plants’ resources via an amazing and clever evolutionary adaptation.
Various First Nations groups across North America traditionally used paintbrush flowers as a food source, although in moderation. It is now known that various species contain toxic alkaloids and some concentrate selenium from the soil. Needless to say, Paintbrush (and other native species in K-Country) are best left unmolested in their native environments to fufill their roles in the natural world and for all of us to enjoy.
See some of the other flowering plants of Kananaskis Country here!