Sedum plants have been used in rock gardens and other landscape settings as groundcovers for many years. However, the high demand for Sedum plants only started recently when green roof installations became increasingly popular in North America (Getter and Rowe, 2007; Monterusso et al., 2005). Green roof installations often require green roof plant producers to provide plant materials with only a short timeframe from ordering to delivery. Understanding the ideal growing conditions for Sedum will allow for efficient Sedum plant production to meet the increasing industry demand.
Growing substrate pH influences plant growth and performance, and different plant species have optimal substrate pH ranges that are unique (Reed, 1996). Substrate pH levels below or above optimal ranges may reduce plant root and shoot growth, influence nutrient uptake, and may even cause plant failure (Marschner, 1986).
Many Sedum species are able to grow in a wide range of soil conditions (Stephenson, 1994) and even under extreme environments such as on the edge of cement driveways. However, a wide tolerance of soil conditions, including different soil pH levels, does not necessarily indicate plants thrive in a wide substrate pH range. Given that Sedum plants are in high demand for green roof installations, there is an urgent need for recommendations regarding optimal growing conditions, including growing substrate pH, for Sedum species.
The objective of this study was to evaluate the hypothesis that Sedum species have optimal growing substrate pH levels or ranges. Specifically, this study aimed to determine the optimal growing substrate pH levels or ranges for the growth of five Sedum species commonly used in green roof installations.
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