Poa annua is a type of grass that is used most often on the west coast of the U.S. It has shallow roots and usually will need to be hand-watered if there is a shortage of rain. Putting greens that use poa annua can have a splotchy or streaky appearance to them, because of the many different strains that compose it. Places other than the golf course consider this type of grass invasive as it tends to grow wildly and rapidly. Pebble Beach is notorious for its poa annua greens.