2017 ASHS Annual Conference

Production of succulents has increased significantly over the past two decades. In warmer climates, succulents have become part of the plant palette in drought-tolerant landscapes. In colder climates, the less hardy succulents are treated as annuals or as accent plants for color bowls and focal displays. Nursery inputs of water and nutrients are not well understood for these crops. Making this situation more complex is the fact that some succulents are winter-dormant while others are summer-dormant in their native habitats. In the following study we quantified water and nitrogen uptake over a one-year growing cycle for winter-dormant vs. summer-dormant succulents in a greenhouse production system. Species used in the study that tend to be winter growers included: 1) Aeonium haworthii, Morocco and Canary Islands; 2) Crassula ovata, Eastern Cape Province, South Africa; 3) Dudleya brittonii, Baja, Mexico; 4) Haworthia attenuata, Eastern Cape Province, South Africa; 5) Portulacaria afra, Kalahari Desert, South Africa; 6) Sanseveria trifasciata hahnii, Nigeria, Africa; 7) Sempervivum arachnoideum, southern Europe. Species used that tend to be summer growers included: 1) Agave victoriae-reginae, Chihuahuan Desert, Mexico; 2) Aloe juvenna, Kenya; 3) Euphorbia antisyphilitica, Mexico; 4) Euphorbia milii, Madagascar; 5) Euphorbia cymbifera, South America; 6) Kalanchoe tomentosa, Madagascar, 7) Opuntia argentiniana, Argentina; 8) Pachypodium lamerei, Madagascar. Plants were grown in 2.4 L containers and watered once a week with 1 L of nutrient solution (100 mg/L nitrogen). Leachates from each container were collected and quantified for volume and inorganic nitrogen content. Because of the artificial growing conditions, some plants did not exhibit a dormancy period, while other species went dormant, as in their native habitat. Water and nutrient uptake were reflected in these growth cycles.