Adam Clarke on Song of Solomon 6:11

I went down into the garden of nuts - I believe this and the following verse refer at least to the preparations for a farther consummation of the marriage, or examination of the advancement of the bride's pregnancy. But many circumstances of this kind are so interwoven, and often anticipated and also postponed, that it is exceedingly difficult to arrange the whole so as to ascertain the several parts, and who are the actors and speakers. But other writers find no difficulty here, because they have their system; and that explains all things.

It is probably not the hazel but the almond nut, that is referred to here.