Matt & Kim wrote:

These are all great suggestions, which I appreciate, but I still
haven't received an answer to my primary question: "Would a
professional gardening or landscaping service be a smart investment in
dealing with horsetails?"

My wife was told by one service that if they came out in the spring,
and sprayed $500 worth of chemicals, it would eliminate (or severely
improve) or horsetail problem. I tend to believe that we could do the
same thing for a lot less by whacking the weeds and using glyco or
casoron ourselves.

Anybody have any advice on which way to go? Is it worth the money to
hire experts or is this just throwing a lot of money away on the
inevitable?

Your last statement about it sums it up pretty accurately. If it were that
simple to eradicate horsetails, they wouldn't be one of the 10 most common
plants in the world and the bane of virtually all Pacific Northwest
gardeners, not to mention others around the globe.

Hiring a professional spraying service (NOT the same as a professional
gardening or landscaping company) will not achieve any better results than
attempting to control this pest on your own. These services are in the
business to make money and repeated and frequent applications are their
stock in trade - ergo, the elimination of the problem is the end of their
business. Get the picture?

You will likely never be rid of this plant - it is tough, persistant and
can grow in a wide range of conditions and the complexity of its root
system and the viability of its spores requires that all your neighbors
invest in the same sort of regular control measures. But you can keep it
in check. Here are a few of the tried and true methods:

- Manual removal tops the list. This obviously requires the most work on
your part but produces the best results. Repeated removal of any of the
top growth will eventually weaken the underlying root system and the plant
will die out, at least in your immediate vicinity. This requires diligent
attention and repeated pulling or mowing. Removal of the roots is
unnecessary and will not help. Initially it can actually aggravate the
problem, as each remaining portion of root can and will generate a new
plant. Keep pulling, as soon as you see any new growth emerging. This
process should start early in the season as the fertile stems (those that
carry the spores) appear and continue on into summer with the vegetative
or foliar growth. Do NOT allow the fertile stems to mature to dispense the
spores.

- Once the top growth has been removed, horsetails do respond to the
pre-emergent dichlobenil (Casoron), which can be applied to ornamental
beds to help reduce recurrence. Do not apply this product in areas were
edible crops are to be planted and be sure to read and follow label
directions carefully.

- In areas where there are no desireable plants (along driveways, ditches,
etc.), the herbicide triclopyr (Brush-Be-Gone) is registered for use on
horsetails and is quite effective. Again, read and follow label directions
carefully.

- Although not registered for use in this manner, glyphosate painted
directly on newly emerging shoots is effective as well. Use a full
strength or concentrated formulation rather than a RTU spray.

None of these methods are a simple panacea - the control of this problem
weed takes persistance and diligence and time. Allow several seasons of
treatment before you see significant reduction. But you can keep
horsetails in check via this method and save many hundreds of dollars (not
to mention widespread pesticide contamination) by avoiding so-called
professional spraying companies.

pam - gardengal
WA State Certified Professional Horticulturist