Independent variable: The amount of light. The independent variable is the one that you change or control.
Dependent variable: The number of flowers on each bush. The dependent variable is the one that changes in response to the changes you make to the independent variable.
Experimental group: The bushes that receive different amounts of light. The experimental group is the one that receives the test variable (the amount of light).
Control group: None. There is no control group in this experiment. A control group does not receive the test variable. It would consist of bushes that receive no light.