Hello! I planted a small globe maple in our front yard 2 years ago and it was doing well until this year. It seems as though it is dying and I’m unsure how to help it or if I just have to cut it down. There are two large maple trees also at the front of our house (other side of sidewalk) which may be taking the nutrients? However, our front garden and a lilac tree seem to be doing fine. I really don’t want to chop this little tree down!
Thank you for contacting Toronto Master Gardeners regarding your Globe Norway Maple (Acer platanoides ‘Globosum’). First of all, it is unlikely that the other trees are the cause of its troubles. It is possible that your tree was injured by the record-setting low temperatures that we experienced last winter. This type of injury doesn’t necessarily manifest until after the tree has leafed out in the spring, as the tree uses up its stored energy and may only show signs of decline once that energy has been depleted. Winter injury is not the only possibility, though. There could also be issues with the root system. Young trees require more frequent, deep watering than established trees, as they have smaller and shallower root systems than more mature trees and can dry out faster as a result. It is a good idea not to lay grass around the tree, but instead apply several inches of mulch reaching about two to three feet out from the trunk (be sure to avoid mulching the area immediately around the trunk; think mulch ‘donut’ versus ‘volcano’). This will minimize root competition with grass for water and nutrients, as well as help the soil retain moisture. Soil compaction is also a possible contributor to your tree’s problems. Compaction can inhibit air and water from reaching the tree’s roots, leading to root loss, which appears above-ground as dying branches.
The photo you provided suggests that much of the tree’s top growth has been impacted. Even if your tree survives and continues to grow, the degree of dieback will severely impact the tree’s ultimate shape. You may be better off removing the tree and planting a new one, making sure to properly prepare the site and provide good care to the tree after planting. If you purchased your original tree from a garden centre, you may be able to obtain a replacement or refund, as many garden centres guarantee their trees for two years and your tree might still fall within that window.
For more information about winter injury, please refer to this resource by the University of Vermont Extension: Winter Injury
For more information about planting trees, please refer to this PDF from Purdue University Cooperative Extension: Planting Landscape Trees and Shrubs