Woad, Bachelor's Button, Elecampane, Tassel Hyacinth, Scabiosa, Croton, and Bugle also provide a botanical blue/indigo color. Why grow a dye garden? If you’re here reading this article, you probably have some inherent motivation to grow plants for pigments and dyes.

Many plants marketed as blue are actually closer to purple. Petunias are a prime example. True blue is a pure blue hue that isn’t shaded with black, white, or any other color. This color is rarely found in nature because few organisms can create the true-blue pigment. Why We Love Blue in the Garden

These flowers can produce shades ranging from blue to purple to pink, and the color depends on the pH and mordant. If you’d like to grow scabiosa at home, keep in mind these plants prefer moderate temperatures rather than intense heat or cold.

Blue is one of the most difficult hues to create with natural plant dyes. Most people turn to indigo or woad for these shades, but both require a lot of work and some rather toxic chemicals to create. You can, however, make a lovely pale sky blue with blue delphinium/larkspur flowers and some copper mordant.