Meyers Homestead and other Walker Ranch trails about 8 miles up Flagstaff Road
Anne U. White Trail west of Lee Hill Road
Hall Ranch trails west of Lyons
Sleepy Lion Trail west of Lyons
Other May nature events
Sugarbowls, larkspurs, shooting stars and wild iris bloom in the foothills.
Abert’s squirrels engage in mating bouts with up to seven males pursuing a female through the ponderosa pines.
Colorado chipmunks, striped skunks and white-tailed deer are born.
Miller moths pass through in large numbers on their way to breed in the mountains; tent caterpillars emerge from cobwebby tents; and little blue butterflies puddle in muddy streams.
International Migratory Bird Day, May 8, celebrates returning warblers and other migrants at Walden Ponds, west of 75th Street. Activities start with the dawn chorus at 5:30 a.m. For details, check boulderaudubon.org.
Photo courtesy of Stephen Jones
Photo courtesy of Stephen Jones
Wicked spines do not deter wildflower lovers from doting on the fragile beauty of cactus blooms.
Finding Pediocactus simpsonii, the first cactus to flower in Boulder County, is reason enough to head for the hills.
The flamboyant flower petals vary from pale pink to torrid fuchsia and usually unfurl in late April, reaching full glory in May. We once saw more than 60 blooming in one spot near the Meyers Homestead Trail at Walker Ranch Open Space. The blossoms close on cloudy days, so go out in the middle of a sunny day to find them.
The globular cactus plants are especially abundant on dry, gravelly ridges where they receive the most intense light, but they also thrive on rocky soils in foothills canyons and have even been found on mountain passes. Although the flowers tend toward shades of pink on the Eastern Slope, they are yellowish on the Western Slope.
Commonly called ball cactus, Pediocactus simpsonii is also known as mountain cactus and snowball cactus. Botanist George Engelmann called the species “simpsonii” to honor Army Engineer James Simpson, who led expeditions in Colorado and nearby states. It’s ironic that “pedio,” from a Greek word meaning flatland, refers to this plant that prefers slopes and ridges. However, Henry Engelmann, George’s brother, collected the first specimen for George in a flat valley in Nevada.
Like many in its family, ball cactus loses water in winter and shrinks into the ground. Some plants actually disappear, only to plump up again in spring. Botanist Bill Weber reports the flowers emit a heavy rose-like fragrance, but we’ve never smelled it. Maybe we’re too afraid of sticking our noses into the thorny network that covers the plant.
Nipple cactus (Coryphantha vivipara) also bears intense pink flowers and resembles ball cactus. However, the flowers, opening May to July, are more vase-like with pointy petals. Less common in Boulder County than ball cactus, nipple cactus prefers the plains to the foothills. C. missouriensis, with yellowish flowers, is uncommon.
Hen-and-chickens (Echinocereus viridiflorus) produces a circlet of chartreuse blooms in May. These small, egg-shaped cacti are characterized by vertical ridges on their stems and are common in grasslands up into the mountains, where they continue blooming through June.
Prickly pear (Opuntia macrorhiza), common on mesas and rocky slopes, produces spectacular yellow blossoms in June. Indians ate the fruits, pads, buds, and flowers, and prickly pear fruits have even been found in coprolites (fossilized feces) of people living 6,000 years ago in Texas. Today, gourmet groceries sell the fruit (tunas) and pads (nopales). Other Opuntia species in the county include New Mexican prickly pear (O. phaeacantha), brittle cactus (O. fragilis) and plains prickly pear (O. polyacantha).
Cholla (Cylindropuntia imbricata) is rare in Boulder County, but cactus expert Bill Jennings has found it blooming near American Legion Park on July 4.
In “Colorado Flora,” Weber writes that except for prickly pears, we should consider all cacti threatened or endangered and refrain from collecting them in the wild, especially since most fail to thrive when transplanted.
Ruth Carol Cushman and Stephen Jones are authors of “Wild Boulder County” and “The North American Prairie.”
