I would expect to pay around £10.00 an hour if you want anyone worth having,
but remember that all the best will already be very busy.
You might find that local parks have people who do extra work in their own
time, also local college having a horticultural course could have possible
candidate, and they could be cheaper, but remember you get what you pay for.

David Hill
Abacus Nurseries
www.abacus-nurseries.co.uk