2. Sweet Alyssum (Lobularia maritima) This low-growing annual makes a lovely white, highly fragrant edging for flower beds, or a fast-growing, beneficial-attracting, weed-smothering ground-cover to interplant in vegetable beds. Numerous studies have confirmed that sweet alyssum is highly attractive to aphid-eating flower flies. You can start with seeds, or buy bedding plants for earlier flowering.
Photo: (cc) Carl Lewis/Flickr