|I have a very shallow bed with a fountain in the middle, surrounded by brick pavers and the earth is only about 2|
|I can imagine how lovely the ferns looked near your fountain, but they do need more root room than the area can provide. For real success you'll need plants with shallow root systems. Some that might look nice include Snow in Summer (Cerastium tomentosum), Sweet William (Dianthus barbatus), Cottage Pinks (Dianthus species),
Coral Bell (Haucheria sanguinia), Candytuft (Iberis sempervirens), Lavender (Lavenduia angustifolia), Moss Pink (Phoix subutata), or creeping groundcovers such as Carpet Bugie (Ajuga raptans), Irish Moss (Arenaria verns), Blue Fescue (Fastuca ovina glauca) or Wintergreen (Gauitheria procumbens), Stone Crop (Sedum species),
Hens and Chicks (Sempervirum tectorum) or creeping Thyme (Thymus species).
Hope these suggestions are helpful.