there isnt, nor is there one for woad or indigo. best advice i can give is for now just get them from a high-level kin member as once you get friend with the men of dunland (need at least lvl61 just to start) you can farm wildflowers (via the farming craft - historian, woodsman, or yeoman) which give nothing but dye mats - including yarrow, woad, and indigo. long term, i'd say level your scholar up and aim for friend with the men of dunland; if you can get the items for turnin and a port to galtrev (or walk/run/ride there which takes longer) from your kin, you can start working on the rep at level 61
As has been noted, the starter areas, and the area in and around Bree in particular. I have never noticed they can be farmed tho, say like ore nodes. I don't know that they have semi-reliable spawn points, which makes it a bit of a gamble finding them. I agree with Monoloco, if there is a way to get them through actual farming, tho it is looong way away if you are low level maybe go for that. And don't forget to check the AH, although in my experience there is usually only a few items (if any) and they can be pricey.