Arum italicum can be spread by birds, which swallow the fruit whole and excrete the intact seeds. A migrating robin might drop seed far from the feeding site. Pamela Harlow Seattle On Wed, Apr 23, 2014 at 9:39 AM, Jane McGary <janemcgary@earthlink.net>wrote: > 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 > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ >