Except for the danger of floods for people who live near big creeks and the Big Muddy, we're in that wonderful time of the year, after frozen pipes and before tall weeds. The signs of both spring and summer are everywhere. Poison ivy, dirty swimming pool water, wild mustard, Canadian thistle, asparagus -- we have all of that in early in May.

A friend and I had been to the Meramec River with our children when we stopped near a beautiful old stone fireplace where iron was smelted for making cannonballs during the Civil War. She fingered some waxy leaves on a vine that clung to the stone. "Sue, come see this beautiful vine."

"Come away," I yelled as I hurried toward her. "Leaves three? Turn and flee!" I couldn't believe she didn't recognize poison ivy! I repeated the rhyme I teach children: "Leaves three? Turn and flee! Leaves five? Let it thrive."

My friend argued a bit and fingered more leaves. Three days later, she called. "Do you know what? That was poison ivy!"

She was sensitive to the oil of that pretty, dreaded plant. So am I -- I've been covered with its terrible rash two times. Once when I was 14 years old and again 20 years later. The rash comes in a few days and lasts about two weeks. The oil is the plant's defense, and it comes when the plant is crushed, broken, mowed or damaged in some way. I scrub with warm water and strong soap after being in the woods.

One early May morning, I was surprised to see asparagus about knee-high. I stopped and snapped off a handful to take to a friend. I should have known to look for it because asparagus usually comes when May apples open their umbrellas in patches along country roads. When the moisture is right, May apples also send another message, "Look for morels." I call those "sponge mushrooms."

Mushrooms on our dairy farm were snow-white polka dots on green autumn pastures. Pasture mushrooms need just the right combination of temperature and moisture in September. They are the same as the white commercial mushrooms with pink gills, which are produced in computer-controlled "weather" conditions in sterilized earth.

My dad taught me, more than 75 years ago, to destroy two noxious weeds -- Canadian thistle and wild mustard. We sprayed the thistle with weed killer and pulled up the wild mustard by the roots before the seeds could mature. Both plants use space, nourishment and moisture that might go to other plants. The thistle's purple flower is Scotland's national symbol, but its bristles seem to reach out and grab you as you pass by.

Wild mustard turns some fields bright yellow in early May because there are so many plants. It looks beautiful but I can't help pulling it up by the roots. It always makes me think of Dad.

I once had our farm almost clear of mustard because I pulled the plants up by the roots. Now I still pull a few for old time's sake; it's a nice excuse to stroll in the warm sunshine early in May.