That is sweadish and means between Bird-cherry and Lilacs. Or in fact between the blooming of these trees. It is also an old saying, meaning a very brief moment. The actual time period is so short that it´s not likely to really exist at all;)
Today I´ve had a quiet day, mostly listening to Anna Järvinen. This song is lovely.
Above is an old apothecary sign, I believe it reads lilac blooms.