Bur oaks (Quercus macrocarpa) shine against a cloudless October sky.

The fleeting season of gold and blue arrived in central Minnesota last week. The golden hues of bitternut hickory, bur oak, aspen and ash glow against a sky the color of a newly opened morning glory — a shade unique to autumn. Along the Snake River in Pine County, MN, the steely blue-gray wings of a great blue heron swoop over the sparkling water.

A great blue heron (Ardea herodias) swoops over the Snake River in east central Minnesota.

Heavenly blue (Ipomea purpurea) morning glories continue to bloom in October.

Closer to the ground, the last of the powder-blue bottle gentians and asters — some with center disks as bold as the sun — bloom among the grasses. Fallen aspen leaves accent walkways, and the heart-shaped leaves of the carrion flower vine wind their tendrils skyward. In a few days, this lovely combination will dampen down to more muted tones, the gentle softness that insulates the earth for winter’s palette of black and white.

Bottle gentian blooms (Gentiana andrewsii) turn dark and dry out as their seeds mature.

Asters (Symphyotrichum novi-belgii) provide nectar to these hoverflies, or syrphids, and many other autumn insects.

Quaking aspen leaves (Populus tremuloides) and moss decorate a walkway at our cabin.

The heart-shaped leaves of the carrion flower vine (Smilax herbacea) add light and color to the October woods.