According to the flood pulse concept (Junk et al. 1989), vegetation responds to characteristics of the flood pulse, including flood timing, duration and rate of rise and fall. However, the response of vegetation will vary depending on plant adaptations, characteristics of the flood or / drought, and whether the flood is regarded as a subsidy or a stress (see Chapter 1). This chapter explores the response of vegetation to water and, more specifically, the water requirements that will promote the growth of vegetation within floodplain wetlands. Water requirement profiles for individual species are provided.