Do not allow lack of information keep you from experimenting with plants for natural dyes. Remember some basics and you will most likely get a lovely and lasting color. If you find a recipe for wool and want to adjust it for your basket cellulose fibers like reed or cane, remember some rules.
1) You will have the best result if you pre-mordant your material. Cellulose (plant) fibers can handle and need more alum than wool or protein fibers. Usually dyers use cream of tartar with alum for wool due to the potential harmful effects on wool. I think any kind of water softener is good with cellulose fibers. If you do not pre-mordant with alum or tannic acid, at least add 1/8 cup alum to your dyebath.
2) For deeper shades of color use alum and tannic acid. Soak your fibers overnight or even several days. Remember to add water daily and stir well.
3) Use the leaves and stems of the red sumac plant for tannic acid.
4) If you are a beginner, make your dyebath and add your mordants to the dyebath. As you become more experienced, mordant your fibers one to four days before adding them to the dyebath.
5) Two of the safest and best mordants for cellulose fibers are alum and tannic acid. Order your alum, don't settle for the grocery store variety. You can order iron or use a rusty nail. If you want consistent results, use powdered iron. Iron will change the color in some dyebaths. Walnut dye will change to charcoal with iron.
6) Remember to rinse dyed fibers with equal water and vinegar to help set the dye.
7) Most basket weavers add plain salt to the dyebath to help set the color. The books I have on wool dyeing do not emphasize the use of salt. But what harm can the salt do the cellulose fibers? They are much tougher than wool.
8) An alkaline solution is OK but don't use a strong acidic solution, especially vinegar.
9) It is important to understand substantive dyes and how the mordanting process differs from that used with berries and flowers.