Clematis

• Clematis is a favorite vine in northern climates that bears a range of flower colors, from cream to purple. Clematis can be susceptible to diseases such as powdery mildew due to their tendency to grow thickly, reducing the flow of air and exposure to sunlight. Fine Gardening recommends planting viticella varieties that resist the growth of powdery mildew and provide easy-care blooms. The purpurea plena elegans bears two to 2-1/2 inch magenta flowers that can grow to six to nine feet tall. The little Nell variety offers delicate purple and cream blossoms. The Betty Corning variety of clematis bears smaller, one to 1-1/2 inch blossoms that turn downward in a nodding form. Clematis varieties that bear smaller flowers tend to have fewer problems with powdery mildew growth.
  
  

Honeysuckle

• Climbing honeysuckle vines are one of the favorites of gardeners. In the past, these flowering plants have often had problems with powdery mildew, but new disease-resistant varieties have made their cultivation more trouble-free. The National Institute for Agricultural Research recommends the Inov71, Inov42, and Inov86 varieties for reliable resistance to powdery mildew disease. These species vary in color from cream to orange-yellow to dark red.
  
  

Creeping Phlox

• Backyard Gardener recommends planting powdery mildew-resistant varieties of creeping phlox in your garden. This low-growing perennial blooms from mid to late spring with pale to deep purple flowers. It can be started inexpensively from seed and requires little maintenance. You should space plants to allow adequate circulation of air and make sure that sunlight is allowed to all areas. Removing all lawn debris from plants is also helpful.
  
  

Climbing Roses

• Powdery mildew can be a particular problem on delicate roses. Fortunately, a number of climbing rose varieties are available that resist infection by powdery mildew. Midwest Gardening Tips recommends the Canadian explorer variety of roses for best resistance. Climbing varieties include the Henry Kelsey, the John Cabot, the William Baffin, and the Quadra varieties for best powdery mildew resistance.