From Master Gardener Pam:
Plants I'll always plant: Perennials, low water, deer and rabbit resistant, attract pollinators and hummingbirds. Butterfly weed (asclepias tuberosa,) Hyssop (hyssopus officinalis,) Caryoperis, Lavender cotton (santolina chamaecyparissus,) Kannah Creek buckwheat (eriognum umbellatum v. aureum,) Penstemon, Sedum, Yarrow (achillea,) Lavender, Tickseed (coreopsis,) Salvia, Rudebeckia, Pincushion flower, Blue fescue (Festuca glauca,) Dwarf fragrant sumac (rhus aromatic,) Lemon lace elderberry (sambucus racemosa,) Hostas, Sweet woodruff (gallum ororatum,) Roses – I usually look for zone 4 or Canadian. Morden Sunrise and Dainty Bess from Hi Country Roses are favorites.
Plants I'm itching to try: Salvia ‘maraschino’, Lead plant (amorpha canescens), Englemann’s daisy (englemannia peristenia)
Forget about it: Oregano, New Mexican privet
From Master Gardener Bonny:Plants I'll always plant: Anaheim peppers
Plants I'm itching to try: Sulphur flower (Eriogonum dimbellatum) -- a native perennial
Forget about it: Hostas—too easily damaged by hail, and they need lots of water in our climate, but put Brunnera in their place!
From Master Gardener Matt:Plants I'll always plant: Blueberries
Plants I'm itching to try: Hickory (Shagbark)
Forget about it: Artichokes
Plants I'm itching to try: None.
Forget about it: 4 o clock, chocolate flower, blanket flower, rabbitbrush, milkweed. Last year the pink smartweed polygonum turned out to be a Japanese beetle magnet. It is a volunteer plant that grows near our irrigation ditch. I left it (while continually picking beetles), as it seemed to decrease beetles on my plum tree.
From Master Gardener Nancy:
Plants I'm itching to try: Scarce Colorado natives such as Eustoma russellianum (tulip gentian); Other natives such as Liatris spicata and Liatris punctata, Clematis virginiana; multiple varieties of penstemon so some are blooming spring to fall
Forget about it: Plants that have a lot of prickles or thorns; Invasive plants that spread underground; Plants that are rabbits’ favorite snack; Plants that will not do well in the Front Range environment