For eleven years, the green roof industry has been running into the issue of finding a lack of Sedum cuttings between November and May. Green roof plant nurseries are not able to produce Sedum cuttings during this time because they obviously never learned better. During this time they rather grow these plants in pre-vegetated plastic or metal boxes, sitting in a controlled greenhouse for bigger sales in late spring and leaving the clients alone later when exactly these expensive and high carbon foot print containers do not acclimate in their final destination. They call themselves green roof plant experts but hardly understand the typical life cycle of the plants they are growing.
When average temperatures drop most Sedums (most plants) store their nutrients and energy produced during the growing season in their stems and roots. The best indicator for that is the changing color of the leaves in the fall and when under stress. Once these reserves are stored in the little stems, they are extremely powerful and “programmed” for rooting - not for producing leave mass. Many Sedums root quicker in winter than in hot summers where they have to deal with high evapotranspiration because of their denser leave mass while their roots are not able to supply them with water to offset the water loss.
Utilizing Sedum cuttings on green roofs can reduce the cost for plants and planting by 90%, assuming the applicators know what they are doing. At the end, the overall costs will drop dramatically which leads into more green roofs and less subsidies from public agencies and non-profit groups. The plant pieces broadcasted in winter are most likely adapted to the conditions in their final location in less than 2-3 months and hardly require watering on hot spring days or in summer. This also reduces maintenance time and costs.
Jörg Breuning: “The lack of common sense and real expertise is the biggest problem in the North American green roof industry. My person is controversial discussed, many feel intimidated based on my experience and that I address problems directly, which are avoided by other professional or trade associations. I see myself as the stimulus in a literally growing industry.
From an environmental point of view longevity at acceptable costs, low maintenance, no supplemental watering, and the long-term health of the plants are crucial for ongoing success. Customer orientated work requires that we adjusted to nature – nature will never adjust to humans”.