How to evolve Tulip? Grassland Trees?

[Delirious]

Trying to evolve a tulip from a daisy, it needs the colour blue and x2 grassland trees....what are grassland trees? google is no help. What am i missing?

[Fortuna]

When you click on a tree and open it's information box, part of the information will tell you what category of plant something is. Birch Trees[i.imgur.com] have under their category "Grassland Trees" which tells you it can help evolve your Tulips. Oak Trees, which are probably the other kind of tree you have right now, by comparison have "Woodland Trees", so they can't evolve the Tulip.