Karol Emmerich, owner of Springwood Gardens in Minnesota recently posted this to Facebook and the Discovering Daylilies page. It is worth the read. See my follow up comments below.
"Shallow-rooted trees growing anywhere near your daylilies are not your friend. They will soak up almost all the water and nutrients in the area, and drastically reduce a daylily’s bud count, height, etc. This link provides an excellent description of common shallow-rooted trees: www.treemusketeers.net/trees-with-shallow-roots/ It notes, for example, that “Cottonwood is genetically programmed to produce shallow roots. It grows naturally in flood plains where waterlogged soils are the norm. The tree’s roots typically grow no deeper than six feet, but they can extend up to 100 feet from the trunk.” The pictures in this post illustrate what can happen even if you were careful when initially constructing your garden beds. No cottonwood or other trees were apparent in picture 1 when these flower beds were created and planted with seedlings about 18 years ago - just some shrubby looking plants in the background - so we assumed all was OK. Picture 2 is what this same area looked like in the summer of 2022. As you can see in picture 3, shallow-rooted trees like these cottonwoods (which self-seed here in the wild) are clearly incompatible with the nearby underground water pipes for the sprinkler system and with growing healthy daylilies. Roots from the same tree 50 feet from its trunk are shown in picture 4, and picture 5 depicts its roots 100 feet away! Maple trees, although extraordinarily beautiful, will create the same issues. Their shallow roots can spread 60 feet from the trunk and dramatically change a daylily’s height and bud count."
My comments:
I have shared comments and pictures from Karol Emmerich before as I find her to be one of the leading daylily hybridizers in the US. This post is significant because it points out a common question here in Vermont---can I plant under trees? This becomes a more common question with gardeners in Vermont's urban locations where lot size is smaller and neighbors may well have trees too. I find the question even more common with those interested in growing hostas and other shade tolerant plants because they often plant first and then come asking about issues a couple years later, sometimes after the surrounding trees have grown even taller. Lilacs and hydrangeas both have shallow root systems that extend well beyond what you think but trees that grow larger such as Vermont's admired sugar maples grow tons of roots. I once planted 30 hostas in individual 20-gallon nursery pots sunk to almost ground level with a 1-inch lip left above ground to slow down voles and other problem critters. It was a lot of work and expense but now twenty years later some that I left are still there from when we moved our flower farm. The pots allow you to control water, fertilizers or other additives. If you are thinking about planting around trees, consider all these points and at very least be prepared to take a shovel and annually cut the roots that are encroaching upon every plant you have placed within the root system.
