If she continues to water every day, she'll continue to have mold. If I remember correctly, north central WA has a climate that is closer to mine than it is to Seattle's. In desert or near desert conditions, you'll probably never be able to water just once a week (unless you switch to native grass). If you have sandy soil, you may need to water three times a week (almost as often as every other day), but you might be able to cut back to twice a week. With clay, you should be able to cut to twice a week with no problem. You're not causing your neighbor's mold. She's causing it.

Thats the same thing thats happining on my hoya, it only happens around the base and then the leaves drie up and fall off. My hoya was a litle over watered when it was out side in the summer, I left it with my mom and she wattered it every day, not making that mistake again. I'll try to stop wattering it untill the first inch of soil dries out.

There is a common term "squirrely" and a few years ago I learned where it comes from. This spring also. I have a large Grecian urn as a feature in my new garden under a Black Walnut tree. I watched a squirrely squirrel jump from the urn to my Krossa Regal and back over and over again until my hosta was flattened. It was enjoying itself until I unleashed my German Shorthaired Pointer on it. They love bombing my things with walnuts, but I have never seen them eat a hosta. What they do is when they smell recently disturbed dirt they dig looking for burried nuts so they might uproot newly planted hostas. I wonder if some pressed garlic will discourage this? Les

You mention "black mold" in Los Angeles area & they rip your house apart. I saw the mess they made of Erin Brockenvitch(or whatever her name was(Julia Roberts played her in movie about different problem) anyway several houses in area of her house got tore to shreds. Well, they were fairly close to ocean so you naturally get lot more mold growing. Most houses have some mold, just take a Qtip & put it in your sink drain in bathroom, run it around & in most cases it will be black!! I have allergies so I have narrow brush that is on end of 6 ft cable so I can scrub it out, I use Comet & rinse well & then hydrogen peroxide& forget about it until next time I clean it. A lot of times the "black" or dark spots in attic is from moisture getting in before the new roof was put on(reason they put new roof on!