Currently citizens of EU Member States have an automatic and unrestricted right to work throughout the EU, including the UK. A significant number of employers in the [care/agricultural/service] sector supplement their workforce with EU nationals, which is a big issue to resolve following the Brexit vote.
The UK Government will take back control of borders and will likely put in place steps to control immigration immigration. Work arrangements will obviously have to be re-negotiated with the EU and its Member States; it is doubtful the new arrangements would replicate the present freedom of movement.
For now, at least, it is business as usual. EU workers can continue to work for you. Any changes to immigration laws will probably only affect those who want to enter the UK after the exit takes place (which isn’t likely until 2018). After this point, it will probably be more difficult to employ anyone from the EU in the long term, but exactly what that means depends on the terms of the exit. If legislation is passed where EU workers need to obtain permission to stay in the UK, there will likely be a long “phasing in” period.