The Best Clematis for Zone 4

About Clematis

• Clematis is a member of the buttercup family, Ranunculaceae, with the name coming from the Greek word for "vine." Clematis comes in many flower forms, colors and blooming times. Flowers can be white, pink, mauve, purple, blue or variegated. They also come in single or double flowers. Some varieties are late-blooming while others bloom later. Clematis are hardy in a wide range of USDA Hardiness Zones from Zone 3 to Zone 8, according to University of Vermont horticulturist Dr. Leonard Perry.

Best Clematis Varieties For Zone 4

• Most clematis varieties can survive even in winters in Zone 4. If you have concerns about the winter temperatures in your area, however, go with the most hardy varieties of clematis to ensure that they will be ready to bloom in the spring. Clematis alpinus, or alpine clematis, is a an early-flowering variety that can grow in part or full shade. Flower color choices are blue, pink and purple. Clematis macropetala is one of the best varieties for Zone 4 and bears small, bell-shaped flowers in purple-blue. It blooms in early spring with a second bloom in late summer. Clematis viticella is a late-blooming variety known for its toughness. It bears white flowers tinged with mauve with foliage that is gray-green, according to FineGardening.

Clematis Care For Zone 4

• Plant clematis in well-drained soil that has been adjusted to a neutral pH of 7.0. A soil test will indicate if your soil is low in phosphorus and requires additional fertilizer to correct this deficiency. Add compost or rotted manure to aid in water retention and drainage. When planting, leave the crown 1 to 2 inches above the soil surface. Fertilize your plants annually with a 3-1-2 or 4-1-2 fertilizer. Clematis require about 1 inch of water per week. Give your clematis plants the best care for zone 4 winters by keeping them moist before the freeze and covering the crown with mulch over the cold months.

Clematis Problems

• The fungus Ascochyta clemitidina can be a serious problem in clematis plant, causing stem rot and leaf spot. It can cause sudden stem collapse just as the buds are about to open, according to Ohio State University horticulturalist Jane C. Martin. Remove the affected stems below the soil line and destroy to preserve the rest of the plant. Powdery mildew can affect plants in poorly ventilated locations. Treat with a fungicide recommended by your local agricultural extension service. Aphids and earwigs may be an occasional problem. Treat the affected plants with insecticidal soap.