Autumn olive flowers are often white, rather than the yellow seen in the posted image. Removal of these shrubs is not easy. It is complicated by their thorns. They should be cut close to the ground. The stubs should be immediately painted with 40% glyphosate (Roundup). Seedlings should be pulled, dug out, or sprayed with regular weed killer. And keep at it year after year after year. The birds will keep bringing it back. The treatment is key. Out transportation department graded a long stretch of highway edge a couple of years ago. They did not treat the remaining stumps and roots. The regrowth is already head high.