Category 2000 contains the angled growing systems. The plants are thus pulled upwards and then drawn (guided) horizontally over to windows and doors. The vertical area of the climbing field sometimes serves only to guide the stem of the plant (which is usually without leaves)... then only one rope is needed. Roses, vines, and clematis prefer several parallel cables. One line systems prevent entanglement. Some plants-- particularly wisteria - require single cable systems to prevent displacement (require increased effort to stay in horizontal positions); angled trellis systems are then only partially suitable. Find out more in the Climbing Plants and Planning sections.