Weeds can affect the growth of ornamental plants in several ways. They compete with ornamental plants for resources such as light, water, and nutrients, leading to reduced growth, development, and flowering. Weeds can also shade out or smother ornamental plants, and some may release chemicals that inhibit the growth of neighboring plants. Weeds can also harbor pests and diseases that can spread to ornamental plants, and their presence can detract from the aesthetic appeal of the garden. Regular weeding and maintenance can help prevent weeds from negatively impacting ornamental plant growth.