Blue Flower Edit
Blue Flowers can be found on pinetree-like Elderwood-trees growing on and among their Leaves in Tundras, Mountains, Taigas and some parts of Forests, but also high up in Canyons and as rare giant trees in Savannahs.
These flowers are blocks that can be placed and even used as building-material, but can also be used for crafting. Blue Flowers usually cannot be found on Snowy Elderwood Leaves right away after world generation, but these Flowers can grow on these Leaves too in time, albeit very slowly.
Elderwood trees can be grown from Elderwood-Saplings (an additional harvest when gathering leaves), but only in fitting environments. Grassland is not always a good place to grow them, but these trees will even grow in Mountains and cold biomes. Elderwood trees can be grown on Grass blocks or also Snow Cap blocks; different to the hints ingame they do not even require any moisture nearby.
Saplings can be fertilized by Pigsy Droppings, but only if the Saplings aren't fallow, because in this case no tree will grow from them at the chosen spot anyway. If Saplings are placed into unfit areas, they will not start to sparkle and stay fallow. The word "fallow" can be read when pointing your crosshair cursor at the Saplings that do not sparkle.
More Blue Flowers will - slowly - grow on Elderwood Leaves with time, so you can lay out flat artificial biomes made from Elderwood Leaves and wait for a few (real time) days until you can collect one or two Blue Flowers there every couple of days or so. The same goes for Red Flowers, Yellow Flower and Wildwood Flowers; not for Autumnwood Flowers nor Weepwood Flowers though.
An even faster method to get more Blue Flowers is to place blocks of Blue Flowers on the ground and pick them up again - once in a while you will obtain 2 flowers at once when doing that. This also works with Red Flowers, Yellow Flower and Wildwood Flowers.
Blue Pigment is used for crafting Blue Beacons, Blue Lamps (Wood Burning Lamps that emit blue light), Purple Block of Goo, Blue Fireworks, Blue Stained Glass, Blue Beds, Blue Concrete, Blue Mosaic Tile Wall, Blue Adobe Floor, Blue Adobe Roof, Blue Adobe Wall, Blue Carpet and Blue Wood Wall.
Blue Flowers can also be used as an ingredient in Basic Health Potions, Stone Mining Cells, Taming Collars, Golden Potions and other crafting recipes that let you choose from different possible flowers.