August 2003

Clematis ‘Inspiration’ By Paul Pilon

From June to September, Clematis ‘Inspiration’ bears dark pink flowers accented by yellow stamens on strong stems that have shown a remarkable vase life of up to three weeks. This compact, half-climbing variety reaches 3-5 feet high and is hardy in USDA Zones 4-9.

Inspiration was bred by Wim Snoeijer in 1993 and introduced to the trade in 2000 by Jan van Zoest of England. The pink flowers are considered a color breakthrough, as most clematis in the durandii species bear purple flowers. Inspiration is vegetatively propagated by means of tip or basal cuttings. The plant patent is pending (PPAF) so self-propagation is prohibited unless you obtain a license.

This variety, with its unique flower color, long bloom time and exceptional vase life, has received rave reviews in European markets, earned numerous awards including the 1999 Award of Recommendation by the Royal Boskoop Horticultural Society, The Netherlands, and was selected as the best introduction at the 17th Salon Végétal, France in 2002.

Production

Most growers will receive their clematis plugs, usually 21/2-inch liners, while they are still in the dormant form. Plant Inspiration into 1-gal. containers using a well-drained potting medium. When planting, I recommend potting the liner deeply so that the crown and one set of nodes is approximately 1 inch below the soil surface, leaving at least one set of nodes above the media surface. If possible, place the support stakes or trellis in or on the container at the time of planting. Young clematis shoots are very tender and can easily be damaged if care is not taken during the installation of the supports. After planting, water in thoroughly using clear water.

I have also observed that it is best to bring clematis out of dormancy slowly rather than immediately turning the temperature up to optimum growing levels. At planting, place pots in a greenhouse with a heat setting of 45° F. After two weeks, raise the heat setting to 52° F for an additional two weeks, then raise the temperature to the final setting of 58° F. During this entire “waking up” process, I set the venting at 65° F.

Inspiration is a light to medium feeder, requiring the pH to be maintained at 5.7-6.4, the EC between 0.8 and 1.4 and the nitrates between 40 and 80 ppm. It is best to deliver nutrients to Inspiration by incorporating a controlled release fertilizer at a rate equivalent to 1 lb. of nitrogen per yard of growing medium. For example, if your time-release fertilizer formulation is 20-9-9, meaning it contains 20 percent nitrogen; you would need to incorporate 5 lbs. of this product per yard of media to obtain 1 lb. of elemental nitrogen (1 lb. is 20 percent of 5 lbs.).

Many growers prefer to fertilize using water soluble fertilizers at a rate of 50-100 ppm nitrate delivered under a constant liquid fertilizer program. To prevent salt from accumulating in the pot, it is recommended to allow a 10 to 15-percent leach fraction when irrigating, meaning 10-15 percent of the water applied drains out of the bottom of the pot. If your watering practices do not contain this leach fraction, then irrigating with clear water every fourth watering will prevent salts from climbing to undesirable levels.

The soil should be allowed to dry between irrigations, but not to the point the plants are wilting. When irrigation is necessary, water thoroughly. Foliar diseases can be reduced by watering early in the day, which allows plenty of time for foliage to dry before nightfall.

Most finished clematis producers usually provide containers to the marketplace with stakes or trellises, which provide support for the vines. As mentioned previously, it is usually best to install these support devices at the time of planting while the plants are not actively growing. Installation of the supports after clematis is actively growing is still possible, but care should be taken not to damage the young, tender vines.

To promote lateral branching and a fuller plant, I recommend pinching back to three sets of leaves, but only one pinch should be necessary. If new shoots do not develop within 10 days, try leaching the pots with clear water as excessive soluble salts might be the problem. If high salts were present, new shoots should develop within a few days after leaching. Training the vines before they become lignified is beneficial, as they become difficult to bend and may break.

Pests and Diseases

Inspiration may on occasion be visited by a few insect pests, namely aphids, whiteflies, thrips and spider mites. Of these pests, spider mites are the most difficult to control, as they feed on the undersides of the leaves where it is difficult to get adequate coverage with insecticides. To enhance your coverage, deliver an adequate volume of miticide using sufficient spray pressure (200-300 psi), causing the leaves to turn or lift up during the application and allowing coverage of the chemical to the lower leaf surfaces. Use of spray adjuvants or spreader/stickers such as Capsil or Latron B-1956 will also help these chemicals coat the leaf surfaces, increasing the likelihood spider mites will come into contact with the pesticide being applied. I have also had luck combining ovicides such as Hexygon or Ovation with more traditional miticides such as Avid or Floramite.

Numerous disease pathogens may attack clematis including Ascochyta, Botrytis, clematis wilt, Fusarium, powdery mildew, Pythium and Phytopthora. Do not apply fungicides containing the active ingredient Etridiazole; the trade formulations include Banrot, Terrazole and Truban. These chemicals will cause severe phytotoxicity and most likely plant death. The fungicide Protect T&O also causes phytotoxicity when applied; the leaves become small and twisted, the internodes remain short and the overall growth becomes stunted. These symptoms can be mis-diagnosed as ethylene injury. Many fungicides are safe to apply to clematis, including Cleary’s 3336, Domain, Fungo, Daconil, Spectro 90, Chipco 26019, Phyton 27, Camelot, OHP-6672, Sextant and Zerotol. Controlling foliar pathogens on clematis should be done on a preventative basis. Apply fungicide sprays every 14-21 days; remember to rotate between chemicals and chemical classes.

Availability

Clematis Inspiration (PPAF) is an exclusive variety of the Ball Seed Company and is available from distributors or brokers affiliated with the Ball Horticultural Company.