Went here after May golden week, also lured by the photos on the internet I decided to find out if this place exist.
I went on May 7,2013. In theory it should be early, but most of the wisteria were actually full bloom!
This place is pretty much impossible to go without a car / bike. Public transit doesn't take you all the way to the place, the closest stop will get you to the dam while the garden is on the other side of it :S
Entrance fee is 1000 during full bloom, price changes according to the flower condition.
There are 3 tunnels, first two is ones we see online, the upper part has a dorm (kind of like a igloo) so you can get stand under the wisteria. The wisteria there are quite spread so didn't stay there too long. The top part is a large flat ground with lots of long wisteria hanging down. Last one is a slop down to the entrance, I personally love this part most as they put many different types in the same area, from afar they become descending colour: purple (blue) pink, white and so on (see photos)
According to the pamphlet that I receive, this place is also awesome for Maple too! Not to mention the maple part is block during the wisteria season.
And BEES! Lots of them!
If you are scare of bees, you may want to give a second thought about this place.
It's packed with bees and the wisteria here are long and drapes down very low, so you can expect tons of bees fly around you.
There's a hotspring nearby, otherwise I don't recall seeing any other facility around.
no lockers but you can ask the admission people to take care of the heavy bag, but they are not responsible for any lost item of course.
I recommend to have someone speaks the language to go with you if you don't speak any Japanese, this place is filled with locals and old people.
There was a website on this place, but they took it down.
I put down the phone number from the pamphlet.