Landscape designer Stephen Suzman likes the groundcover species Senecio mandraliscae for its fast growth and distinctive chalky-blue fleshy foliage. A native of South Africa, it grows 12 to 18 inches tall with masses of 3- to 4-inch pencillike leaves. greatgardenplants.com
Can you recommend some good sources for buying seeds and offer some tips for starting plants from seed?
—Julia Tomer, Pittsburgh
Starting plants from seed, whether flowers, fruits, or vegetables, requires a little research. Some seeds will need an early start indoors; others can be sown directly in the garden. Most seed packets will provide you with all the information you need to have a successful season, as will the websites of many online purveyors. While I still enjoy receiving the odd seed catalogue or two by mail—Baker Creek Heirloom Seeds (rareseeds.com) is a favorite—I do most of my seed shopping online.