We have a very large beautiful sycamore in our back yard. My roommate
thought it would be nice to build a flower garden around the base of the
tree, but something tells me that doing so would be harmful to the tree’s
root system. Is this true? I would love to hear your thoughts.
I think it should be safe to plant
shallow-rooted, shade- and drought-tolerant perennials and small bulbs
under your sycamore (I’m assuming you mean Platanus species, and not
sycamore maple, which is Acer pseudoplatanus). You just need to be
careful not to pile soil on top of any exposed roots, and try not to
scrape or scuff any roots when you are planting. This tree does have
spreading roots so they may extend out some distance.
More information about the tree can be found on the pages of the U.S. Forest Service.
Some of the plants which may work well in your garden are:
Lamium (but not the invasive Lamium galeobdolon)