Paintbrush Tank

EVERY TIME I ENCOUNTER a paintbrush flower, I momentarily lose my breath. It feels like a small miracle that these springy bursts of color are real, living things. Paintbrush flowers—members of the genus Castilleja—are often associated with transformation, intuition, and creativity.

Paintbrush plants are also hemi-parasitic, which means they photosynthesize and produce some of their own energy, but rely on host plants for most of their nutrition. To access these resources, Castilleja possess specialized root-like structures called haustoria, which pierce the roots of unsuspecting host plants to siphon off nutrients. This interaction is not one-dimensional, though. Ecological studies indicate that host plants can influence the paintbrush that parasitize them, affecting their growth or how attractive their flowers are to pollinators. For example, when parasitizing lupines, which are nitrogen-fixing legumes, paintbrush often produce more seeds and attract more pollinators than paintbrush that parasitize grasses. The bright red and orange of paintbrush flowers may also attract more pollinators when paired with the purple of lupine. In nutrient-poor ecosystems, paintbrush can support higher rates of nutrient cycling because they produce high-quality litter, making scarce nutrients available to nearby plants. More recent research has investigated how hemi-parasitic plants may foster diverse soil microbe communities, which can benefit the entire landscape.

I am an ecologist by training, so I can nerd out on this type of thing. But I love how these associations show us that relationships between living things are more intricate and nuanced than we might realize. When I see paintbrush flowers now, I think about how these bright jewels of subalpine summer are harbingers of a vast connected world underfoot. They remind me to breathe a little deeper, walk with a little more reverence, and not to resist gratitude when it ripples through my bones.