This Week's Podcast — A Replay: The "Weed Sheriff" Strives to Stop Marauders Before They Invade
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As many of you know, I am obsessive about the problem of invasive plants. Next to global warming, invasive plants might be among the great challenges to gardeners – especially to this gardener. The problem is a serious threat to agriculture and the forestry industry. How did aggressive alien plants get here? 
What are some of the worst offenders? What is being done to control them? What can we do?
Dr. Alan Tasker (the unofficial “weed sheriff”) is a noxious plant expert and my guest today. Alan has served as the USDA APHIS Senior Regulatory Policy Specialist since 2012. His current duties include managing data development to support the “Not Allowed Pending Pest Risk Assessment” category of imports for Plants for Planting. He is the senior regulatory policy specialist and previously served APHIS Plant Protection & Quarantine as National Noxious Weed Program Manager.
Just about everyone knows that USDA stands for United State Department of Agriculture. What does the acronym APHIS mean? Dr. Tasker explains “Animal and Plant Health Inspection Service.”
The loudest complaint I hear is about mile-a-minute – a common name for several different plants including the form known as Polygonum now called Persicaria perfoliate. I had this plant one year after the floods, but luckily and surprisingly it did not return.
Some weeds in my garden include: garlic mustard, Japanese stilt grass, purple loosestrife, multiflora rose, bush honeysuckle, forget-me-not and Canada thistle.
I often hear that there are no rules in gardening. Well one might be to avoid planting a potentially invasive alien plant. The worst plant I accidentally introduced to my garden is Ixeris stolonifera. It came from a gardener in Vermont who had never had a problem with it. It just goes to show that some plants behave differently in various locations. This plant spreads by runners and seeds – I will never be able to get rid of it.
Most states have lists of plants that are not supposed to be sold, but these bans are rarely enforced. A list of some of the worst offenders include: goutweed, chameleon plant, euonymus burning bush, purple loosestrife, Norway maple, barberry, Russian and autumn olive, pampas grass, yellow flag iris, privet, Hall’s honeysuckle and even ground covers vinca, English ivy and pachysandra.
Dr. Tasker’s list is headed by stemless thistle, witchweed, fireweed and the phytotoxic giant hogweed (Heracleum mantegazzianum with Dr. Alan Tasker, above). Blisters appear if the sap gets on the skin in sunlight. In the shade, nothing happens.
Here are some links to State and Federal lists of invasive plants.
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