It depends a lot on what the flowers and shrubs are, different plants require different methods.
If you can identify what the plants are, you can then check on how to propagate them with information found on gardening sites on the internet. The RHS are usually very good.
If the plants are perennials, for instance, it can sometimes be easy to remove a portion from the root-ball, pot it up and grow it on, which can be a quick and easy way to increase your stock.