My 2-packs consist of one tree about 4" in height, and the smaller tree about 3" in height (Three photos on left are HO size).    For shorter version, order my N scale 2-pack (Cactus section) which are two trees about 2 1/2" in height (pictured with pliers above).    Trunks & limbs are Kakhi in color.    If desired, these can be customized by the customer by drybrushing.    To be more realistic, you'll want to either gently clip off roots & plant in pre-drilled hole, or bury roots in Sculptamold, caulk or plaster and paint surface.   
 
Joshua Trees are found in harsh desert environments.    (Also consider my Palo Verde trees & cacti.)