The S1400 is a string trimmer with a rotating head that uses nylon line for trimming grass and weeds. It is not designed for the heavier duty tasks of hedge trimming.
If you need to trim hedges, you would need to purchase a separate hedge trimmer. John Deere does produce a range of hedge trimmers, so you could look into those models.
However, it's important to note that the S1400 does not have the necessary attachments or power output for converting it into a hedge trimmer.