The olallieberry is a cross between a youngberry and a loganberry, each of which itself is a cross between a blackberry and another berry! A bit confusing, but it's best to know that olallieberries have a distinctive, sweet flavor and look like an elongated blackberry. They are primarily grown in California and have a very short window of harvesting time from mid-May until mid-July. This means they are in season right now! Olallieberries are delicious both fresh and cooked and are excellent in jams, jellies, and pies.