In Good Thyme - by Mariana Graham

Appeared in WNT, May 30, 2001

Last week's most commonly asked questions at Master Gardener clinics Island wide concerned rhododendrons and dandelions. In the rhodie department, questions ranged from how to plant them (in well-draining soil amended with generous amounts of compost or other organic matter) to why are leaves browning and curling (planted beneath eaves of house; get insufficient water). One person wanted to know why his rhodie's leaves were turning yellow. It seems that this well-intentioned gardener treated his prized plant to a generous serving of dolomite lime, something acid-loving rhododendrons can't tolerate. Keep lime, wood ash and mushroom compost away from your rhodies. Save it for the lilacs, which love the stuff.

Dandelions were the number one weed problem reported at recent clinics. Spot treating with a glyphosate product such as Roundup or Kleenup will do the job, but if you have a field full of dandelions, or hate to use chemicals except as a last resort, what can you do short of renting a goat?
Vinegar has been touted as a good organic weed killer. It does destroy many weeds, but it isn't the perfect solution. Weeds with long taproots such as dandelions or thistles will usually die back when treated with vinegar, but there's lots of life in that taproot, and it could regenerate. Vinegar can also sterilize the soil, so you'll kill the weeds, but you may not be able to grow anything else in the vinegar-treated area either. It can take an entire growing season before all traces of vinegar have dissipated.
A few weeks ago I reported on a new tool specifically designed for removing dandelions, taproot and all. I have since personally tested "Clint's Dandy Digger" and it works very well. I also tried out the Deluxe Dandy Digger, which not only make's child's play of dandelion removal, but does a good job of ousting my least favorite weed, thistle. Maybe we ought to have a "worst weed" competition. Send me your nominations and I'll print them. The winning weed will be exterminated. Oh yes, back to the Dandy Digger. You can purchase it (or borrow it for a free trial run) at the Greenhouse Nursery in Oak Harbor, or order on line at www.clintsdandydigger.com.

The digger is indeed dandy, but even armed with this formidable weapon, I wouldn't want to tackle an entire field of dandelions. In that case, the easiest solution is to learn to love them. Think positive: the plant is edible, its flower is pretty, and it certainly can't kill you. The next weed we're going to discuss can, however.

Poison hemlock (Conium maculatum) is a highly toxic plant that can kill people and animals when any part of it is ingested. History tells us that the Greek philosopher Socrates was assassinated with a poison hemlock cocktail.

This European native is a member of the carrot and parsley family, and people have been poisoned mistaking it for an edible. It grows along roadsides, hiking trails, wet areas, weedy lots, and even backyards, where its deadly beauty is appreciated by misguided gardeners. A biennial, during the first year it produces a rosette of fernlike leaves. The next year it sprouts a tall (4 to 10 foot) stem that blossoms with lacy white flowers between May and August. It resembles the familiar Queen Anne's lace, but can be distinguished from it by closer observation. Its stem is hollow between nodes and is usually covered with purple blotches. The hollow stalks are attractive to children, who have been poisoned merely by blowing through them. The plant also has an unpleasant odor, often described as "mousy," or like a musty basement.

According to the County's Noxious Weed Control Board Program Coordinator Judy Feldman, small stands of poison hemlock can be successfully pulled if the soil is moist enough. Wear gloves, as small amounts of toxins can be absorbed through the skin. Judy also suggests chopping them with a hoe just below the crown. Don't put the plants in the compost or leave them where children or animals can get into them. Dead stalks remain poisonous for several seasons. Don't burn them; even the smoke is toxic. Large stands of poison hemlock may be eliminated with application of the chemical 2,4-D applied when the plant is young and growing.

If you think you may have poison hemlock on your property, you can get help with positive identification as well as control suggestions from Mrs. Horton, Contact her at 679-7327 (Susan Horton replaced Judy Feldman as Island County Noxious Weed Coordinator in 2003).

Garden questions or comments? Call 675-6611; fax 675-2732, or wnt@whidbey.net. Mariana Graham is an Island County Master Gardener and member, Garden Writers Association of America.