The columbine is infested with spider mites; they suck out liquids from leaf cells, leaving whitish-brown empty cells. The webbing is another indication of spider mite infestation.

Look at the leaf undersides with a hand lens/magnifying glass to see lots of spider mites there.

Spider mites like hot, dry dusty conditions. If your columbine is on a S exposure in full sun, the location may be contributing to the spider mite problem.   You could consider moving the columbine to a part sun, cooler location next spring, or make sure that it gets some water on the leaf undersides. Using a water wand hose attachment, spray water in a fine mist up and onto the leaf undersides 2-3 times a week during hot weather. Water alone can deter spider mites.

More details on spider mites from CSU Extension: http://extension.colostate.edu/topic-areas/insects/spider-mites-5-507/

PS-

rock mulch and brick hold and reradiate heat back into the plant - promoting spider mite populations.    Suggest you move the columbine to a cooler location next spring.

You're right - I did find little bugs on the undersides of the leaves. Your information is very helpful. Thank you so much!