Complex sentence: Poison oak is a widespread deciduous shrub throughout mountains and valleys of California, WOW even in shady canyons it thrives & riparian habitats it commonly grows as a climbing vine with aerial (adventitious) roots that adhere to the trunks of oaks and sycamores.
Split into simpler sentences: Poison oak is a widespread deciduous shrub throughout the mountains and valleys of California. It commonly grows as a climbing vine with aerial (adventitious) roots that adhere to the trunks of oaks and sycamores.