The beautiful and well-known Mount Usher gardens run alongside the River Vartry at Ashford in County Wicklow. County Wicklow is known as the garden county of Ireland. Follow the signs on the M/N11 for Ashford which is roughly 15/20 minutes north of Arklow or 15/20 minutes south of the Loughlinstown Hospital roundabout in County Dublin.
An excellent collection of plants is on display at Mount Usher gardens along the beautiful banks of the River Varty. The garden has a number of suspension bridges across the water that provide excellent viewing points.
The Mount Usher gardens which date from 1860 were designed by Edward Walpole and follow the naturalistic approach to planting and landscaping. They are accessible by wheelchair and there is an Avoca cafe and some shops on site. When I visited today, the entrance fee for one adult was 7.50 euro. Add lunch to that and it would be pricey enough outing so my advice is spend the money on the gardens and save on the lunch unless you can happily afford to enjoy both.