Ask Mr. Smarty Plants

We are assuming you refer to Campsis radicans (trumpet creeper), a high-climbing, aggressively colonizing woody vine to 35 ft., climbing or scrambling over everything in its path by aerial rootlets. From our webpage on this plant in our Native Plant Database:

"Trumpet creeper grows tall with support. It climbs by means of aerial rootlets, which, like English Ivy, can damage wood, stone, and brick." 

We would say that the stucco walls of your house could very definitely be damaged by this vine. Also, even if you transplant these vines to somewhere else, there will still be suckers in the original location propagating themselves like mad, going right back up to eat the stucco. According to this Floridata website Campsis radicans, it is hardy from USDA Hardiness Zones 6 to 10, but Longmont appears to be in Zones 4a to 5a, which might keep the vines from being so aggressive, and also explain the failure to flower. As to the fertilization, if you are using a high nitrogen fertilizer, such as in lawn fertilizer, that encourages the green leaves and there is little energy or interest in the plant for blooming. Of course, it is deciduous which, as you already know, leads to pathetic bare vines going up your wall for a good part of the year. This plant requires full sun, which we consider to be 6 or more hours of sun daily; that could also be impeding the flowers.

We checked on another vine, Bignonia capreolata (crossvine), which is related to the trumpet creeper, evergreen and not as aggressive. It requires sun or part shade, and blooms early in the Spring. However, it is not native to Colorado at all, with East Texas being the nearest area to which it is native.  It grows mostly in the southeastern United States and, like the trumpet creeper, is only hardy to Zone 6. 

With 18 species of Lonicera (honeysuckle) native to North America, we found 1 that is native to Colorado, Lonicera involucrata (twinberry honeysuckle). It shows up on this USDA Plant Profile as being native to the Longmont area. It is more like a bush than a vine, and is only hardy to Zone 6. It can grow in sun, part shade or shade (less than 2 hours of sun a day), is deciduous and attracts hummingbirds.

As you can see, there is no ideal native vine for your location. You could, if you wished, try to get more sun on the existing trumpet creeper, stop giving it fertilizer and see if it will not only survive, but perhaps bloom. You could try crossvine, a more desirable vine or the twinberry honeysuckle to see if either will survive and bloom in the same spot. We can't make that decision for you, obviously, nor even predict with any accuracy which one would be best.

From our Native Plant Image Gallery:

Campsis radicans

Campsis radicans

Bignonia capreolata

Bignonia capreolata

Lonicera involucrata

Lonicera involucrata