Growing Concerns 8: Poison Ivy, Saving lupine seed

Poison Ivy

After sharing a nasty case of poison ivy with my two year old, I did a lot of research but none of the books show a picture of the culprit or how to get rid of it. Please inform parents of exactly what to look for, how to keep these plants from coming back and what to do if you suspect your child has touched one of these plants of gloom. - A.M. -

The key to dealing with poison ivy: identifying it We all know it's dangerous but a many of us can't identify it - even after suffering a case of it!

Poison ivy (Toxicodendron radicans) always has 3 leaflets, but has a lot of variation beyond that. It may look like a vine, a bush or small tree. It may creep on the ground or reach 50 feet up a tree. It lives in sun or shade, but I find it most frequently at the edges of woods. The best way to learn what it looks like is to have someone show you the real thing. Naturalists at local nature centers can give you a quick lesson. Your guide can show you how to recognize the 3 leaflets and distinguish them from the look-alikes that often grow in the same places: brambles (they have prickers; poison ivy doesn't) and box elder seedlings (box elder branches are in pairs along the stem; poison ivy branches occur singly).

Janet must work in poison ivy and teach those who work with her to identify it. Steven has proven to be hypersensitive so he's spared this chore! We point out the real plant or send students to the Internet (as in our issue Grow 647, Poison Pen).

To get rid of poison ivy, treat it like any perennial weed. Dig it out, or cut the main stem and keep cutting off new growth every two weeks until it has exhausted the reserves in its roots. You might consider spraying it with a non-persistent herbicide such as Round-up®. After defeating adult plants, stay on the lookout for seedlings. Poison ivy berries are valuable winter food for many birds, who deposit the seeds in our gardens.

Only 3 of 10 people may be immune to poison ivy, and many dermatologists say no one is immune over a lifetime - it simply may take several contacts over a period of years before a sensitivity shows up. So don't take chances. Don't work in or near it on hot, sweaty days when your skin pores are wide open. Cover your skin completely. Janet wears long sleeves, gloves, long pants tucked into boots, and plastic bags over her hands and arms. Wash afterward with cool water (keep the pores closed!) and non-abrasive soap (no tiny scratches to give the oil easy access) within 15 minutes of contact, before the oil has time to soak in. Avoid touching your face until you've washed, and be careful as you undress not to touch bare skin with clothing that was exposed.

Even with precautions, she will sometimes “catch” poison ivy. As we write this she is looking at her arm, at red blisters that appeared a day or so after oil from broken leaves or stems got on her skin. Blisters erupted first on her fingers, a day later on one arm, two days later on the other, but we both know the rash is not “spreading.” It simply appears earliest where the skin is thin or the oil lay heaviest. You know after all your research that you didn't catch poison ivy from your daughter's blisters. You came into direct contact with the oil when you hugged her before the oil had been absorbed into her skin.

Our own experience is that keeping the blistered areas clean and dry makes them heal more quickly. We hope you are both healed by the time you read this.

Saving Lupine Seed

I would like to see an article on harvesting seed, is lupine ripe when the seeds are white or black? What about petunias, marigolds, zinnias, also tomatoes, peppers, etc. Does one need to dry them or is it okay to put them in plastic baggies? - G.O. -

Most flower and vegetable plants' seed can be harvested when ripe, cleaned, dried, and stored in a cool dry place. In dry storage all the seeds you list and most others we grow in Michigan will last a year, often much longer.

It's fun to pick the biggest, best, healthiest plant and save its seed. Just be aware that seeds from hybrid plants produce plants that may be quite unlike the parent.

Let seed ripen on the plant for best results. The ripe head or pod will be dry and crisp but not yet shattered or split. If you aren't sure it's ripe, put a paper bag over the pod and attach the bag to the stem. Ripe seeds will fall in the bag. Fleshy fruits like tomatoes should be just a bit overripe but not rotten when harvested for seed.

Clean seed by removing bits of pods and other chaff, or pulp. Pulpy seed may be soaked in cool water for a couple of days. The pulp will float, the seeds fall.

Moisture can rot stored seed. Dry seeds thoroughly in a cool, airy place. No high temperatures, please. To test for dryness, seal some in a glass jar for a day or so. If condensation forms in the jar, the seed wasn't dry enough.

Keep seeds in sealed containers. Baby food jars work fine for me. Store in a cool, dry place. Refrigerator temperature, between 32° and 40°F is ideal but even my 60° back room stores seed well because it's also dry.

Good information on saving seed in general and handling many flower and vegetable seeds in particular is available in the excellent catalog from Seed Savers Exchange. Look it up on-line
or become a member to receive the printed copy and support a worthy organization.


Originally published 9/18/93; updated 10/15/20