Superb for summer color, grow clematis for bright accents on a trellis or fence. For best success they require a rich, alkaline (sweet) soil and a site with good drainage. To maintain soil alkalinity mix 1/2 cup of agricultural lime into the soil each spring. Choose a location with sun at least half the day, and keep the roots cool with a thick mulch, or plant annuals or perennials in front to shade them. Clematis vines are fast growing, hardy, and increase in size and beauty every year. Plant several varieties to extend the blooming period.