I visited these lovely National Trust gardens a few days ago and they greatly surpassed expectation. All the flower beds are well kept and there was a profusion of huge colourful flowering plants, many heavily scented (the gorgeous yellow azaleas most of all).
There are many paths through the formal part of the garden and some through a wooded area too beside the burn and bridge. Many of the trees are mature and quite magnificent, especially the enormous Wellingtonia on the front lawn.
There was no one manning the wooden kiosk beside the car park when I was there but an "honesty box" was on the wall by the door. There's also a tea/coffee machine just inside where you can make a brew!
The gardens are on the west of Cardross, 18 miles north-west of Glasgow.
I'd like to go back there again before long as my time was limited the day I visited!
(See the website here)