Tibetan carpets from the 19th century (perhaps earlier, though mostly carpets from the 19th century survive) are relatively restrained in terms of design and coloring, carpet makers at that time being restricted to a narrow range of natural dyes including madder (red), indigo (blue), Tibetan rhubarb (yellow) and Tibetan walnut (browns and greys), with a few other local plants producing yellow and greenish colors.