Clematis has been called ‘Queen of the flowering vines’ for good reason. They’re the most prolific and dependable flowering vine for the Upper Midwest. There are many clematis cultivars, all with pretty colors, but my favorite will always be Jackman, with its strong growth and masses of royal blue-purplish blossoms.
A few key steps will make any clematis bloom more profusely:
- When planting a new clematis, expect it to take at least 3 years for the root/crown system to become robust enough to produce shoots plentiful enough to fill a trellis. Once in place, clematis rarely if ever need dividing.
- The ideal location is the east side of a house or other building, getting full morning sun, but shaded from the hot afternoon summer sun. Northern exposures might not provide enough sun. Clematis will grow, but flowering might be less prolific.
- Clematis follow the old saying of wanting their ‘head in the sun and feet in the shade.’ Short shrubs can be planted several feet away from the clematis to shade the roots, or annual flowers can be used to cast shade. This is especially important if an east exposure isn’t available and clematis is on south or west side.
- Clematis want cool, moist soil, as opposed to hot, baked roots. Mulch the base of the clematis with a 5-inch-thick layer of shredded bark or wood chips. Especially important on south or west exposures.
- Clematis respond extremely well to fertilizer. Apply a cup of 10-10-10 granular fertilizer in May and again in June around the base of the vine and water in. Or mix 3 or 4 gallons of Miracle Gro solution and apply at two week intervals in May and June.
- Water regularly, say a good soaking every 7 to 10 days in the absence of rain.
- Here’s a final tip that I learned many years ago that is relatively unknown, but it doubles the volume of vines and flowers. As the clematis vines begin new growth in May, pinch out the central growing tip of each emerging vine. Where there was one shoot, 2 will arise. Continue this pinching of all shoots as they grow through May. Each single shoot becomes two, doubling the volume of vines and flowers.
- Jackman clematis blooms each summer on ‘new wood’ produced the current growing season. Let the tops remain over winter, and then prune back to 6 inches above ground level about the time new buds are just appearing at soil level in spring.