Can I visit Fuji Shibazakura on 4th June?

I read that the festival is until 31 May. If i go on 4th June, can i still enter, even if there is less to see? Or will there be no pink flowers left to see?

No, the park is not open outside of the festival period. I also doubt that the flowers will still be in bloom. Even now, the flowers are already clearly beyond their peak.

I just visited the festival today and most of it is gone now. There are a few patches of pink left but it's quite sparse now, probably will be even worse over the next few days. Good news is they are not charging admission fees now, so I only had to pay for the bus ride to and from the festival site.