Plants that tolerate boggy conditions
If you have a high water table or think that a flooded or waterlogged garden is likely to become a way of life, then reconsider your planting scheme and choose plants that will thrive in damper, boggy conditions. Most plants that like wet ground also like rich soil, so dig in plenty of organic matter before planting and mulch borders each spring with compost.
Trees such as willow (salix) and birch (betula) are well known to tolerate sitting in wet soil. Other ornamental trees suited to smaller gardens include: common pear (Pyrus communis), Paulownia tomentosa and Amelanchier lamarckii. Shrubs like weigela, kerria, hydrangea and cornus are also all happy getting their feet wet. Perennials to look out for include: hosta, carex, astilbe, iris, zantedeschia, rodgersia, primula, rheum, ligularia and the stunning royal fern; osmunda regalis. Ivy also copes well in occasionally waterlogged soil.
However, if you have areas of ground that are likely to flood and be under water for long periods of time, look out for plants that will cope with this, such as pond marginals. These include: lobelia cardinalis, juncus, marsh marigold (caltha palustris) and species of iris that have specially adapted roots such as laevigata, enstaa, sibirica and versicolor.