The "Spring farewell day" ... on June 29th?
Yep, sounds like a Russian holiday alright :)
The context is that it's the oldest inside Russian joke to make up random occassions when drinking. You feel like having a drink, but can't justify it - no problem, drink to the revitalizing power of parsley or to bid spring farewell or something as silly.
Though I did hear about the "Saint Mother Mary of Egypt" day which was about every second Friday if you were to believe a heavy-drinking madam two floors down from where we lived.