Gardens in Netherlands?

What would be the best time to see some of the beautiful gardens, Spring ? Summer ? and what are the names of these gardens ?

spring - Keukenhof (in Lisse).
also try to attend a flower auction

Definitely in spring! It is amazing all the flowers.
I went in a place called Keukenhof (in Lisse), and was so beautiful!

http://www.keukenhof.nl/

Spring would be great, I think the flowers should be here in a month to six weeks.

To find gardens to visit, go to the tourist information website at www.vvv.nl and do a search. A lot of the site is in English.

defiantly the spring I travel to Holland a lot and spring around late March to late may would be around the best time to see them

There's the Keukenhof, of course, but how about the botanical gardens, they're lovely as well! And much less touristic.
There's one in Amsterdam but my favourite is the Hortus Botanicus in Leiden (near The Hague)
Go in late spring or early summer and hope for lack of rain..

there is a bunch of parks and the flowers bloom in spring