There are many different ways of avoiding plant damage that can be implemented before considering the use of metaldehyde-based pellets.
Selecting plants that are resistant or less attractive to slugs and snails is one option. Others include using traps or barriers, or surrounding susceptible plants with a rough surface such as gravel.
Alternatively, you can attract the pests away from your prize blooms with sacrificial plants, but remember to collect and dispose of them at regular intervals.
Click for more information on protecting your ornamentals and edibles.