Xeriscape is a type of landscape for saving water with properly prepared soil and use of plants that require less water to grow and thrive.  Xeriscape is pronounced zear·i·skap (short i, long a in skap). "Xeriscape is a systematic concept for saving water in landscaped areas." (Xeriscape is a registered trademark of Denver Water, Denver, CO and is used here with permission.)

Seven fundamentals of Xeriscape:   
•   Planning and design - for water conservation and beauty from the start.

•   Create practical turf areas - of manageable sizes, shapes, and appropriate grasses.

•   Select low water requiring plants - and group plants of similar water needs together. Then experiment to determine how much and how often to water the plants.

•   Use Soil Amendments - like compost or manure as needed by the site and the type of plants used.

•   Use mulches - such as woodchips, to reduce evaporation & to keep the soil cool.

•   Irrigate efficiently - with properly designed systems (including hose-end equipment) and by applying the right amount of water at the right time.

•   Maintain the landscape properly - by mowing, weeding, pruning and fertilizing properly.

For more information on Xeriscaping view these web sites:
Colorado Wise Water Council
PlantTalk Colorado

Xeric Trees
View this link to see a list of Xeric Trees as provided by the Colorado State University Denver County Cooperative Extension Master Gardener

Trees that will not do well in Cheyenne are:
Chilopsis linearis - Desert willow
Catalpa ovata - Chinese catalpa
Catalpa speciosa - Western catalpa (there are three known to be growing in Cheyenne, but they are struggling)
Koelreuteria paniculata - Golden raintree
Quercus imbricaria - Shingle/Laurel oak
Quercus robur - English oak
Quercus robur 'Fastigata' - Columnar English oak
Quercus undulata - Wavy leaf oak