City Creek Nature Notes – Salt Lake City

November 20, 2016

November 20th

Filed under: Colors, Plants, Tansyaster, Weather — canopus56 @ 5:17 pm

Green Spurt

Noon. Today, temperatures have returned to the low sixties. Looking down canyon from milepost 1.5, the high canyon walls are free of snow and are now green tinged. Overnight, with the warmer temperature and the water from melted snow, those high lands have turned green. Perhaps it is simply a change in contrast from the water soaking into vegetation, or perhaps with cold water and sunshine, the grasses had a spurt of chlorophyll production. Along the road, there is just one insect – a fly bolts by – and all color has gone. There is just one purple tansyaster. Wood’s Rose bushes are a dusky scarlet, and they still retain a few of their red bulbs.

The parking lot is again full of cars, and the overflow goes down the entrance road and on to Bonneville Drive. Residents are getting in some walking before true winter arrives.

In Thoreau’s “Journal” on November 20th, 1853, Thoreau observes how a male marsh hawk while in mid-air flips a mouse to his mate. The hawk is aiding his mate in feeding their young.


September 23, 2016

September 23rd

Contrasts in Color

5:30 p.m. Yesterday’s storm and cold continues through most of today, and it still rains during this afternoon’s jog. The storm is driven by a low pressure system that has stopped directly over Salt Lake City and the canyon. The clouds that soaked me last night have had time to travel around the circular storm track, and I feel same clouds that soaked me last night have returned for another try.

Some trees respond immediately to the rain and cold. River or water birches (Betula accidentalis H.) turn a bright yellow almost overnight. At the guardhouse gate at mile 0.0, the horsechestnut trees begin to turn. Their leaves become brown around the fringes and the color works towards the center of each leaf. The Gambel’s oaks have begun to turn in response to the cold. When they turn, the leaves go directly to a shriveled tan color.

The rain and diffused overcast light emphasizes the brightest color leaves, and the canyon is a study in color contrasts. The deepest red comes from western poison ivy (Toxicodendron rydbergii) and a chokecherry tree hidden behind a clump of Gambel’s oaks at picnic site 10. At that location, a sole Box Elder tree has also half turned, and with one-half green and one-half yellow leaves, the tree stands out with a bright light green hue. The brightest red-orange comes from a few select maples. A light blue and light purple are found in a few remaining roadside weeds, including some tansyasters. The brightest yellows come from two immature narrow leaf cottonwood trees and clumps of dried milkweed stalks. Most larger cottonwoods have not yet begun to turn.

It rains continuously through the night and into the half of the next day.


September 20, 2016

August 8th


4 p.m. Principal insect pollinators in the canyon are butterflies and bees. Near the red bridge between picnic sites 6 and 7, two common roadside flowering weeds are next to the road: a purple tansyaster (probably Dieteria canescens, the hoary tansyaster)and a bull thistle (Cirsium vulgare). The aster is covered in a flock of 12 small cabbage white butterflies. Both the cabbage butterflies and the plants are invasive species. The other major butterfly pollinators of the canyon are the black and white Admiral butterfly and earlier in the season, the yellow tiger swallowtail. The thistle is covered with a red rumped bumble bees, probably the central bumble bee (Bombus centralis) The bumble bees do not have the usual yellow and black striped abdomen of the more familiar honey bee. These bumble bee abdomens are white and reddish-orange banded. Dragonflies also rest on the thistle and act as pollinators. Rarely, wasps can also be seen pollinating flowers. In past years, I have seen the large ground burrowing bumble bee emerging from their nests in the side of the road. This year there are none. I am not a trained botanist or biologist; these are the best amateur identification that I can make.

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