Some believe that the “little, brown colitas” are what is left after harvesting of marijuana.
The song may be referring to the fact that at all times anyone who visits the hotel feels relaxed and quiet- as if they have smoked/eaten a lot of weed.
The plant in question may refer to marijuana (from the Spanish word for small plants related to cannabis) – or it might refer to incense cedar tree branches which line the entrances of some Indian bazaars; such branches are often used in religious ceremonies and come from trees indigenous to Mexico and Latin America, not California.