So let's start by asking a question - where did the scale come from in the beginning? From the environment...from the air, from outdoors, "out of the everywhere into the here." Meaning, the bugs are already around you. You did well to control them on your houseplants, now don't worry so much. If you want to put the plants outside, go right ahead. There are predators out there that control them most of the time. The reason you saw ants in your plants (oh gosh, I said a funny) is that the ants were feeding on the honeydew excreted by the scale, much like aphids, aphids and scale being in the same order of insects. Yes, you should discard the potting medium the infested plants were in, because of the possible presence of eggs. Also the pots that you used should be thoroughly washed and disinfected with a dilute solution of bleach. You should do this with old pots before putting in new plants anyway.

I planted a 12 ft hedge of Gateway JPW (a supposedly shorter variety!) in a fairly dry area near my house, hoping to keep them in check. Much to my surprise, although they did not outgrow their space width-wise, they soon became tall enough to grow into the eaves of the house. After about 3 more years in which I cut them down by half each year in June (that kept them down to 6-8 feet) I gave up and decided to remove them. Not being able to stand the thought of digging out a 12 by 6 foot area, I used Roundup. One application did the trick. A few years later, when renovating a part of the same bed, I did have three JPW stems sprout up. Although these are also quite tall, they don't take up much space in this large bed (and are not near the house) so I haven't quite decided what to do with them yet. I'm not sure if these are a gift from the birds, or seeds from the orignal planting that came to the surface during the bed renovation. I had no seeding, whatsoever, during the 6 years that the original Gateways were in my garden. Sorry, I have no idea about the roots of plain JPW, but my Gateways, despite their huge size, did not have runners or hard to kill (by Roundup) roots, unlike the roots of the much smaller Chameleon plant (Houttuynia cordata 'Chameleon') which required (and still requires) reapplication of Roundup periodically and which I doubt I will ever be completely rid of.

I would first reach for light horticultural oil, like Sunspray, if they still market that. This can also be mixed with insecticidal soap for a fairly effective spray for scale and a bunch of other pests. Then, if you feel you need heavier weaponry, the aforementioned Bayer systemic-the type with imidacloprid as the active ingredient-would be my next try. Malathion would also work, if you times it right to get the crawler stage of the scale. That's why I would first go with the systemic product-a much wider window of effectiveness. +oM

So I have quite a few large areas that appear to be infected with pearl scale. It got bad last summer and I didn't realize it was pearl scale until a neighbor mentioned it was likely that, and sure enough, I've found the bastards in the soil. I have also found grubs, and was assuming the grubs were causing all the damage. I did my first treatment of soil insecticide last week (prior to finding the pearl scale) and had planned to keep up with that. But now I'm really discouraged as I'm reading the pearl scale is almost impossible to get rid of. My neighbor mentioned using sulfur and swore that he had them once and it worked. Has anyone tried anything but digging all the soil up? Thanks in advance.