What about the lawn are you trying to get away from by changing to another type of plant? Anything as short as a lawn will need a lot of weeding for as long as the planting is present unless the site conditions and the kind of plant chosen are an absolutely perfect match. It's a lot quicker and easier to mow and trim a lawn. And if you don't water it during the summer in a summer dry climate area such as Colorado you don't even have to do that all of the time.

Have a look at this website. Plant select grows a line of plants specifically for Colorado's climate and soil conditions.

High country garden in Santa Fe will send you a catalog. Loades of ideas and pics.

Pimple Adjuga

Creeping Thyme

Keep in mind that photo shopped images pulled from the Internet will have very little basis in reality. Creeping thyme will NOT be happy in a lot of shade and creeping phlox never grows as robustly as the above photo would indicate and is in bloom for just a few short weeks in spring.

Both creeping thyme and creeping phlox need absolute full sun and sharp drainage to do their best. I have found the thyme to be short lived, unreliable and prone to die off even under good conditions. Creeping phlox can grow as robustly as in the picture above, but the bloom period is three weeks max. The rest of the year it is a rather non-descript, even bland groundcover that tends to look pretty ratty end of season before bloom and new growth happens in the spring.

If you are wanting to replace your lawn with a meadow look, unless there is a compelling reason, there is no need to limit yourself to plants that stay as short as a mowed lawn. Reduce the size of the lawn and plant a flower meadow. It will only need to be cut down or mowed once a year at some point in the winter. In a real meadow there are no weeds. Only the truly thuggish or obnoxious need to be culled.

Purple ajuga is very pretty, flowers in spring. FWIW - we planted it in 3 areas, died in 2 years. Our soil is clay.

Embo is right on the money as far as lawn being easier maintenance. If you are willing and able to do the kind of maintenance a garden requires, then a meadow can be managed in place of a lawn. If you aren’t willing or able to do regular weeding (including tree and shrub seedlings), water as needed, cut back spent plants and generally keep a garden looking nice, a wildflower meadow is not a realistic option.

As far as Christopher’s comment about there being no weeds in a real meadow, at least in my area the weeds are

-invasive plants like buckthorn, Japanese barberry, and Euonymus,

-native woody plants (because if they aren’t weeded out it becomes a forest, not a meadow), and

-certain undesirable plants such as nettles or poison ivy or prickly Rubus.

I would love to see a photo of the site.

-How large is the area?

-What kind of trees do you have? Have you done a study of the amount of sun and shade available in various parts of the yard?

-Would it make more sense to plant beds of plants with generous paths in between rather than trying for a continuous meadow? Regardless, think about placement of paths so you can access various parts of the yard.

-Are ticks an issue in your area? If so, having more plants, particularly if they are taller, will increase your tick habitats vs. a mowed lawn.

Realistically, meadows are full sun environments. So if you still want to pursue this idea, you will want to look at part sun or shade groundcovers, and they won’t likely be heavy flowering except in early spring. If you are in a part of Colorado with access to a botanic garden or arboretum such as the Denver Botanic Gardens, visit there. See what they are using for ground covers in part shade. See if your local library has any of Lauren Springer Ogden’s books available to see what she uses in similar sites to yours. Visit any local garden centers and nurseries (not big box stores that often stock unsuitable plant material for a particular climate) to see what they offer to suit your needs.