Wilsonii This fruitless cultivar derives from the Manzanillo. It is drought tolerant once established, and it is also fire and disease resistant as well. The multi-trunk trees are dramatic and show off the beauty of this olive tree cultivar. Their hardiness and adaptability allow this tree to live for hundreds of years. The Wilsonii olive tree is fruitless and will not produce the mess of olives, nor will it produce the pollen that aggravates a lot of people with allergies.