Good to know! I have a gold tansy in my cottage garden growing with wine cups, salvia and perennial heliotrope and stachys. That said...we don't have mosquitoes, but our neighbors do. We still can't figure it out. That tansy is NEW this spring. We have lots of lavender, nepeta, rosemary, oregano and thyme, so we've always figured that those plants are repelling the mosquitoes (and flies). Those also attract beneficial insects and birds. We have frogs in our stream/waterfall. So, some of the critters are also eating the bad bugs. Cameron Here is a link that might be useful: gold tansy in first photo

"If it is labelled noxious in your state, the owner of the property must remove it - a call to the town may be in order." This is not the case in WA state. The noxious weed/invasive species list is broken down into 3 classes with only the Class A weeds requiring attention. Tansy ragwort (Senecio jacobaea) is a Class B noxious weed and plain ole tansy (Tanacetum vulgare) is a Class C noxious weed. Control is encouraged with Class B&C weeds but NOT mandated. Since we have not yet seen the plant in question, it could very well be either tansy ragwort or just the tansy on the neighboring property. Cutting them back is a decent option. Personally I'd be far more concerned about the broom invading my property than either of the tansies.

Several insects were introduced years ago as biological control for the tansy ragwort. They reduced the population immensely. Typically, some tansy ragwort will be present every year, more in some years than in others. That sort of activity is required for survival of the bio-control agents. Have you seen any purple & red "butterflies?" If so, they're cinnabar moths, the parents of the cinnabar caterpillars which do a stellar job of eating the tansy to nubs. See this http://oregonstate.edu/dept/nurspest/cinnabar_moth_clup7.html

I have officially geeked out about this plant. I love Lacy Phacelia. Its my new favorite rose companion. It's pretty isn't it? And it's already attracted so many hoverflies that they aren't just eating aphids...they are making babies and the larvae are eating aphids far away on other plants that aren't around the Lacy Phacelia! Diane and Natasha here's a photo showing the Lacy Phacelia in pots, but you can see that Corsican mint I was talking about in the background around the border of the pots. It's a groundcover like pennyroyal, but it likes part to full shade. I have it in pots around my berries. I also have a little "lawn" of it in the front yard near the shade of a redwood. So when it starts to grow too far out from the edge of the pots I just divide it and put it in the "lawn." Side note, that onion about to flower on the left came from food scraps of store bought organic green onions that I planted. How cool is that?