The soaproot and the edible supermarket yuca are NOT the same species. They aren't even in the same family.

"Yuca" is the cassava root.

http://www.dcn.davis.ca.us/vme/ARNHA/soaproot.html is one of the soaproots (bulb, actually) and Yucca elata is also used. Neither of them are available in supermarkets.

The yuca root is also used for surfactant purposes. Indians used it for hair tonic.

I rubbed some in my hand a while ago and although it doesn't foam at all, it does provide a little stickiness. I washed my hands with soap and a half hour later my hands became sticky again when I applied water.

http://www.tandjenterprises.com/yucca.htm

Yes, they are selling yucca but they also demonstrate the foaming on youtube. Here's a link to an old navajo lady washing her granddaughter's hair wth yucca root.

There is no question that commercial yucca liquids foam as does fresh yucca that the Indians use. My store bot version probably does not foam because it is too old and dried out.

Sorry here's the link.

http://www.pbs.org/wgbh/mystery/american/navajoland/yucca.html

No, your store bought root isn't foaming because it is not the right plant species.

Here's why SCIENTIFIC names are critical ...

Supermarkets carry CASSAVA roots: species name is Manihot esculenta, common name is "yuca" (one "c")

The Navajo woman is using the SW native yucca (not "yuca") species named Yucca schidigera

Expecting them to act the samew ould be like expecting to get milk from a "sea cow" just because it's close to "cow".

Thanks, that's what I wanted to know.

Do you know if shidegara has as much sticking power as it does wetting agent?

I don't know.

If I use herbicides or insecticides, I use the commercial wetting agents or surfactants because they usually have high-paid chemistry researchers and all kinds of lab equipment to test the stuff with.

Yucca schidigera is usable as a shampoo, but most of the Navajo I know use Suave from the supermarket. The traditional soaproot is used for ceremonies, but not in daily life.