Boulder Wildlife This Week

What’s blooming in Boulder Open Space the week of June 22, 2026?

If you take a walk down the trails near Boulder, what will you see this week? As you start from the trailhead, you might see more introduced species blooming, like Musk Thistle, Creeping Bellflower, Field Bindweed, Broad-leaved Sweet Pea, Alfalfa and some species that are already going to seed, like Curled Dock. While you might not often think of grasses as 'wildflowers,' right now grasses are blooming! Two introduced species are common, including Smooth Brome and Orchard Grass. Look closely to see the bright yellow anthers of Smooth Brome. And Orchard Grass meristems are delicious this time of year. If you've lived in Boulder for a while, you also might notice that the Smooth Brome is much shorter this year than usual — likely a result of low snowfall winter. Pricklypear cactuses (genus Opuntia) are in peak bloom right now. These plants bloom synchronously in order to maximize the potential for cross-pollination. There are two common species here, Prairie Pricklypear (*Opuntia macrorhiza*), which has only a few spines in each bunch and the spine bunches are qutie far apart, and Plains Pricklypear (*Opuntia polyacantha*), which seems to be slightly less common and has many spines in each bunch and higher density of bunches. The latter species also has an unusual trait for a plant — it has thigmonastic stamens . This means that the stamens move when touched by a pollinator in order to increase pollen uptake. Both species often grow together (i.e., sympatrically). There are also lots of trees and shrubs out right now with fruit, including the rather bitter and still-unripe Chokecherries produced along racemes (i.e., the berries coming from a single stalk);, the red and ripe Morrow's Honeysuckle (hairs on the backs of the leaves differentiate it from the similar Tartarian Honeysuckle); the green and still-ripening Boxelder seeds (called samara). Skunkbush Sumac is abundantly fruiting right now, with its reddish, bunched fruit. You might see some greenish spheres that look like berries on hackberry leaves, but these are actually a type of gall made by the Hackberry Nipple Psyllid. Many other wildflowers are in peak bloom right now, including the Curlycup Gumweed (note the recurved spines and very sticky flower head and the dried-up basal leaves); Prairie Coneflower (beautiful cone-shaped flowers); Manyflowered Gromwell (shorter plant with dense yellow flowers, where the length of the flower (corolla) is twice the length of the surrounding green sepals); Sulfur Buckwheat (umbels of small greenish-yellow flowers), Little Sunflower (large, beautiful); and Pinewoods Geranium (pink/purple flowers with darker veins).