Kathleen wrote, >Working on a wetland mitigation site last week, I found three >patches and two seedlings of Arum italicum. My question to the PBS >members in temperate climates is this: How invasive is this >species? It's listed as invasive in the state of Oregon, which is 25 >miles to the south, and it's in a natural area that is supposed to >be left alone. I suspect it needs to come out, though that may be >difficult, given the likelihood of deeply rooted corms. If there's that much arum in a wetland, it does need to come out. It will have to be dug -- the tubers can survive herbicide application. It probably arrived via garden debris being dumped, or on the treads of logging equipment. Common garden Kniphofia has been found in Mt. Hood National Forest (Oregon) far from cultivated land and probably arrived that way. Arums have large seeds that don't travel far. The state of Oregon is somewhat erratic in what it designates as invasive. Arum italicum spreads rapidly in some gardens here, but not in others. It seems to prefer moist, retentive soils such as the silty soils deposited by rivers; some in my former garden on gritty subalpine soil barely survived. Oregon has even declared Cyclamen coum invasive, and the only motive I can imagine for that is that some official visited Boyd Kline's famous garden in Medford and saw the decades-old drift of that species (C. hederifolium is much more widely adapted, but I don't think it's on their list). A. italicum is present in my new garden but I haven't started quelling it yet as I don't need its spot for anything else (the Spanish bluebells [Hyacinthoides campanulata] are a different matter!). I also have Arum italicum var. albospathum, which one visitor this spring took for a Zantedeschia because of its showy white spathes. I haven't planted it out yet but will do so when it's dormant this summer, along with some other Arum species that are taking up too much room in my bulb collection. I'm not worried about these plants invading in the suburban neighborhood where I now live, and they will make good ground cover in difficult sites near conifers (mine or the neighbors'). Jane McGary Portland, Oregon, USA