Just moved in to a new home, have a Norway Maple in our yard, and getting conflicting advice

Asked September 15, 2020, 1:57 PM EDT

Hello! Thanks for your service, and I hope you are well. We moved to Grant Park in NE Portland in April. I had previously participated in Backyard Habitat Certification in NW Portland, so, I have a basic working knowledge of gardening. I slowly figured out that the 40 foot plus tree in our new back yard along the back lot line fence is a Norway Maple. I getting conflicting and strong:) opinions as to whether to keep or remove it. It is a messy tree and has an extensive superficial root system. Our landscape designer, who is also trained as a Backyard Habitat site inspector, recommends we remove it. However, another friend in the conservation field with a degree in forestry points out that the tree has some positive benefits and recommends we keep it. So, my question: The landscape designer came out to respond to my idea of removing lawn, adding native plants, and working toward Backyard Habitat Certification. She said that the Noway Maple was allelopathic and should be removed. She added that under story plantings would not survive under the tree. I tried looking up citations to verify this information, and found conflicting statements. Are Norwegian Maples allelopathic? Is it true that nothing else will survive in their presence? Thanks! Susan Weedall

Multnomah County Oregon

3 Responses

Thank you for your question, Susan. I surveyed scientific findings on this issue (site:edu or site:gov), rather than reading 'popular' articles (site:com). I can share that there appear to be few studies on the allelopathic side of this plant's characteristics, probably because it has such a rich list of other negative traits. (I assure you that a perusal of the research papers would not be the highlight of your week, but can give you the sites if you want.) Here is the best (and most readable) resource with what I would deem a reliable opinion: https://www.agriculture.nh.gov/publications-forms/documents/norway-maple.pdf I hope this is helpful. Good luck!

Thanks for your quick response! You shared a very helpful reference. In appreciation, Susan