"We found a whole jungle of smartweed!" yells Elizabeth Jones, and half a dozen second-graders tramp after her, through the woods near the Washington Sailing Marina to the patch of smartweed, a ubiquitous plant with a tiny pink flower. Despite the pink flower and the green leaves, smartweed, according to Mariana Gasteyer, the kids' art teacher at Capitol Hill Day School, "makes a nice lemon-yellow dye."

The woods are full of smartweed, chicory, agrimony, poke berries and goldenrod, and the kids are gathering the weeds up in plastic garbage bags to take back to school and boil into natural dye the way the Indians did. The class is studying Indians and plans to weave the natural-dyed wool into an Indian wall hanging.

"almost every plant has a dye property," explains Gasteyer. "almost every dye falls within the green-to-orange range, depending on the mordant you use. Mordants are chemicals used to treat the wool so the fibers will open up and accept a color. I won't let second-graders work with chemicals, so I'll mordant the yarn myself before we dye it."

Argimony, explains Gasteyer, holding up the relevant pages of the Golden Guide to Weeds and of Roger Tory Peterson's Guide to Wildflowers, looks like a tiny daisy and usually makes a greenish-yellow dye.

"what color does goldenrod make?" asks Paul McClung, breaking off stalks of the weed and depositing them in the bag.

"a very nice yellow," answers Gasteyer. "i guess the Indians wore a lot of yellow," observes Paul.

There's one weed in the woods that Gasteyer calls the "mystery flower," and the kids leaf through the fields guides to try to identify it.

"i think it's cone weed of some variety," says Gasteyer, "but it's hard to identify because the petals have already fallen off."

"it looks like this," says Gwen Johnson, pointing to an illustration of ticweed sunflower. Gasteyer agrees, and from then on the plant is known as ticweed sunflower.

"where does agrimony go?" asks Chris Zintner, carrying an armload of the weed in search of the kid with the agrimony bag. When all the weeds are packed in the right bags, there are two full bags of agrimony, ticweed sunflower, and golden rod and lesser amounts of chicoryand pokeberry.

Back at the school, Gasteyer shows the kids skeins of yarn that's already been mordanted, a word that comes from the Latin word for biting.

"you use about four tablespoons of powdered mordant for each pound of wool," Gasteyer explains. "i dissolve the mordant in cold water, then bring it slowly to a boil. After it boils, I let the wool cool down in it , then rinse the yarn in water. And I have pots I use only for dyeing. You should never use any cooking pots or utensils. The safest mordant -- and the easiest to get -- is alum, which you can buy in drugstores."

The skeins Gasteryer mordanted in alum are off-white. Those treated with copper sulfate are green, while the wool mordanted in a pot filed with water and iron nails is brown.Wool treated with ammonia is a pale beige.

"the Indians sometimes mordanted with urine, because of the high ammonia content," Gasteyer tells an adult visitor, without suggesting that process to the kids.

Four king-size pots of water are already simmering on the stove and the kids set to work breaking up the weeds and tossing them in.

"it's turning like tea," says Skyler Stegall, who is on the ticweed sunflower detail.

There is another pot for smartweed and one for goldenrod and when all the weeds are in there is nothing to do but wait.

"when it smells like cooked spinach then we'll know it's ready to put the yarn in," says Gasteyer, who is the offered lots of varying opinions about spinach. After about 15 minutes, a strong odor wafts from the pots but not everyone identifies it with spinach.

"it smells more like artichoekes," says Morgan Fishman.

Gasteyer has labeled each skein as to mordant and dye so the kids will be able to compare the colors afterward. One skein of each mordant goes into each dye and the kids push them down with paint paddles.

"this goldenrod is so golden I'm going to take it out," says Gasteyer, spearing the skein with a paint paddle and carrying it to the sink for rinsing.

When all the skeins are rinsed, they are hung outside on a railing to dry.There are dark browns and pale greens and several shades of tan and yellow, but everybody likes the light orange -- made by ticweed sunflower dye on wool mordanted in alum -- the best.

"natural-dyed wool has a softness, a harmony that can't be duplicated by chemical dyes," says Gasteyer. "no matter what the colors, they seem to go together."

SOMEDYEING TIPS Goldenrod, smartweed, chicory, agrimony and ticweed sunflower all make good dyes and are available in abundance. If you don't know them, consult any field guide to weeds or wildflowers, If you find other weeds, experiment.

To mordant, buy alum (potassium aluminum sulfate) at a drug store.Dissolve about four tablespoonfuls per pound of wool in a pot of cold water, bring to a boil and put in the yarn tied in skeins. The real wool -- it doesn't work with synthetics. Turn off the heat and let the yarn cool down in the mordant. Rinse the wool in cool water. An adult should do the mordanting. Cooking pans and utensils should never be used. If you want to try other mordant, they are available through The Mannings, RD2, East Berlin, Pennsylvania 17316.

Bring a pot of water almost to a boil, then throw in the dye material. The quantity isn't important -- just leave enough room for the yarn. When the dyepot smell like cooked spinach -- after about 15 minutes -- put in the yarn. Push it beneath the surface of the water, but don't stir it.

When you have color you like, remove the wool, rinse it and hang it up to dry.