I have a Japanese red maple tree at the front of my house. Sun hits this area all day, it receives sun and rain at all times, and is planted in clay, topsoil and mulch on top. I would like to know which shrubs, ferns and flowers grow well under and around this tree?
While the area around your tree receives full sun all day, underneath your tree you will need to consider plants and that enjoy or tolerate part-sun to shade conditions. Most nursery plants today have labels indicating planting preference – full sun, part sun/part shade, or full shade. This should give you some guidance if you are wandering through a garden centre and a plant catches your eye.
A shrub under your Japanese maple may not thrive: it will be competing for water and soil nutrients with your maple’s roots. Shrubs would be better sited a little further away from your tree. If you are thinking of adding a shrub to your front yard landscape, you could check some of the major nurseries’ websites which offer samples of landscape plans showing optimal placement of trees and shrubs to scale.
The Toronto Master Gardeners have produced useful garden guides on ferns and perennials for shade which will give you some ideas:
In addition, there are several interesting blogs online in which garden designers offer their ideas for companion plantings with Japanese maples. Here is a link to one of them, to get you started. This writer mentions many lovely spring flowering bulbs which you might also like to consider: https://www.gardenia.net/guide/Companion-Plants-for-your-Japanese-Maples
Best of luck with this fun project.