There is actually nothing wrong in keeping your plants the way they are but if you want your garden to appear decent and clean, pruning is one way of doing so. Pruning is basically done to keep the plant from growing too big. When pruning plants, you have to always consider how the plant grows. If for example a plant blooms from new wood like some species of clematis or buddleia, you would prune them to make space for more flowers.
Some plants that grow slow sometimes do not require pruning at all while some do. When you are pruning, you have to have the right tool to help you do the task. A good pair of secateurs and or a sharp spade would do the trick. The proper way of pruning is cutting the stem cleanly and slightly bends away from the bud. It is also vital for you to remember when to prune. Plants that bloom in the winter, spring or early summer like shrubs, roses and certain species of clematis usually have flowers growing on their stems. These plants are better off being pruned after they have new blooms so as to prepare them for a new set of flowers for the year after.
To avoid the risk of new shoots being frozen, it is best to prune around late winter. Trees on the other hand and bigger shrubs are best pruned this season on the other hand. It will be easier for you to spot diseased and or damaged branches and also shaping the tree.