The utmost importance in an arrangement is the overall harmony and balance. It is possible to combine two or more flowers in one floral design, but in this case choosing flowers that are compatible with each other is of utmost importance. In other words, the key to a well_balanced arrangement is to choose flowers that can strengthen the beauty of each other. What's important to getting the most out of the components of an arrangement is the harmony between the floral material and the container, as well as the overall balance. No matter how beautiful a flower may be on its own, if it does not harmonize with the rest of the material, the balance is lost and the beauty of the flower is wasted.
There are three types of flower designers _ designers that create arrangements based upon following floral design recipes which others originally created, those who create custom_made flower designs for each order, and those that can do both. It is not a given that the judgement will be good for each of these types of designers. However, the judging really comes down to whether or not the resulting design is liked by the customer and fits with their preferences. Since each type can receive positive feedback on their designs, it really doesn't matter which one to choose to become. It will come down to how much creativity and artistic license one prefers to exercise as the same excellent customer service skills are required for each type.