The information below is from Washington State and King County noxious weed information for 2009. New lists of noxious weeds are published annually. I think the information will help you compose a letter.

Three cultivars of Hedera helix and one cultivar of Hedera hibernica are Class C Noxious Weeds in the State of Washington.

Here is the link to descriptions of these four types of English ivy.

Class C Noxious Weeds are weeds that are already widespread; removal is NOT required by law. However, individual counties can adopt removal programs as they see fit. Here is the complete list of Class C noxious weeds in Washington.

King County also has more information on a website about noxious weeds.

King County does not require control or eradication of any of the four English ivy cultivars. Although control is recommended, it is not required.

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Date 2008-01-10
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Ivy is a tough plant to eradicate, as I imagine you already know. The resources I have consulted indicate that manual removal methods are more effective than chemical methods. Ivy apparently has an excellent defense system against chemicals. I could find nothing in the literature that suggested using bleach to kill the roots of Hedera helix (English ivy).

Here are links which may be of use to you.

From the Washington Native Plant Society's Ivy OUT.

From King County Noxious Weed Control.

From Portland, Oregon's No Ivy League.

Local garden writer Ann Lovejoy's article in the Seattle Post-Intelligencer. Excerpt:

Why not just poison it? Using herbicide on ivy is both futile and dangerous. Ivy's waxy foliage repels herbicides, which run off to damage nearby plants and pollute water systems.

To safely and steadily get rid of ivy, begin by cutting all vines that have scrambled up trees or posts. Remove as much as you can reach from each trunk. If you miss a few stubborn scraps here and there, don't worry about it. Just be sure that none of the vines remain uncut or are left dangling.

Now remove all ivy at ground level by pulling strands and prying roots with a small hand-mattock or hori-hori (Japanese farmers' knife). Even if you miss a few roots (as you will), they won't all sprout back.

Finally, mulch with a combination of woodchips and compost if you plan to replant soon. If you just want to keep the ground clear for a while, use coarse wood chips for mulch.

To keep the mulched area clear, check it two or three times a year. You can quickly remove any new shoots that appear, along with as much root as possible.

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Date 2007-06-29
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