Caragana arborescens, or Siberian pea-tree, is not recommended to plant due to its tendency to spread aggressively. This species is a non-native, hardy, low-maintenance shrub from Siberia and China, often used as an understock for decorative cultivars. While it is resilient and tolerant of heat, wind, cold, salt, and poor soils, it is not recommended for planting due to its reputation as a messy shrub in Ontario. The plant's prolific seed production can lead to dense seedling populations, and its small thorns can be an unexpected inconvenience. However, its early leaf sprouting and extended photosynthesis period give it a competitive advantage over other plants and is tolerant of heat, wind, cold, salt, and poor soil conditions.