Geraniums have been popular garden perennials for a long time, and have lots of devotees. Consequently, there are lots of good sources of information on the internet. A good start is provided by the Open Directory Project's geranium category. For a primer on erodiums, this page from the UK gives a good overview.
Stimulus control is the phenomenon of a stimulus increasing the probability of a behavior (operant response) because of a history of that behavior being differentially reinforced in the presence of the stimulus.
Critical control point (CCP) is a step, or procedure in a food process (from its raw state through processing) at which control can be applied and as a result a food safety hazard can be prevented, eliminated or reduced to an acceptable level. A CCP is any biological, chemical or physical property that may cause food to be unsafe.