In general, hedge shears are used for trimming hedges, shrubs, and bushes. Their effectiveness depends on the model you buy, as some come with stronger blades than others and are able to break through thicker twigs and branches. You can use hedge shears to trim hedges back and prevent them from overgrowing, and you can also use hedge shears in a decorative way, pruning hedges and shrubs into certain shapes. If you find yourself in another situation in the garden where a cutting implement is required, hedge shears might be able to get the job done, but you should remember that they're designed mainly for use on hedges and pretty thin branches, so shouldn't be used to cut anything that is too thick or hard.