Damp soils are a gardeners’ paradise. Many plants with bold, lush, exotic foliage thrive in damp situations. Damp areas can include water features, stepping stones, board walks and other features to create an interesting focal point in the garden.
Damp soils tend to be in the shade and can be of two types – peat or clay. Peat soils are free draining, easy to work with, are rich in organic material, such as leaf mould, and the plants respond well to regular mulching and applications of a complete garden fertiliser.
Clay soils retain moisture and can be difficult to work with as over time the build-up of water can rot and kill plants. Applying gypsum, which worms take down into the clay, helps break down the clay particles over time and improves soil structure. Digging in plenty of compost and organic material to the planting area or raising beds will improve drainage, making clay soils more workable. Regular mulching also helps to improve clay soils.
When to plant
Damp soils can be planted at any time of the year, just be sure to water plants through dry periods.
How to plant
It is important that plenty of compost, mulch and organic material are dug into the soil before planting. Dig the planting hole slightly wider and deeper than the root ball. Add a slow release fertiliser to the planting hole and mix in well. Soak the plant in a bucket of water before planting. Remove the plant from its container, run a sharp knife down the root ball in several places to encourage new roots, especially if the root ball appears solid. Place the plant in the hole and firm soil around it. Plant to the depth of the plant’s original container. Water well.
Use a slow release fertiliser at the recommended rate in spring. Always water fertiliser in well.
Mulching is very important. Mulch in late winter or early spring and again in mid-summer. Mulching keeps weeds down and improves soil structure.
The need for watering will be restricted to the hot summer months. Using Saturaid on clay soils will help water penetrate down into the plant’s root zone.
Trees and shrubs
If you have space, there are a few attractive large trees that thrive in a damp situation. We recommend alnus (alder), cordyline (cabbage tree), casuarina (sheoke), cyathea (tree fern), kahikatea, phormium (flax), pseudopanax (lancewood), sophora (kowhai), quercus palustris (pin oak), salix (willow),taxodium (swamp cypress). It is important to check the height that the tree will grow to ensure that they are suitable for the position in your garden.
Palmers handy tip: Deciduous trees can be better suited to damp areas because in winter they allow sunlight in which helps dry out the soil.
We recommend ferns, both tree and ground ferns are all good choices, carex grasses, dipsacea, secta and virgata, elatostema, mazus and some flax varieties or use native reeds and rushes like juncus, apodasmia or leptocarpus.
Many perennials love a damp situation; we recommend astilbe, cyperus (papyrus), filipendula (meadowsweet), gunnera, hosta, iris, lobelia cardinalis, pratia, lysimachia, mimulus, primula, zantedeschia (arum lily).
This list is by no means comprehensive. Please ask at your local Palmers store for more information on plants suited to your conditions. Click here for our online online guide to creating water gardens and information on aquatic plants.
The most common pest in shady and damp locations is slugs and snails. This is especially so for plants with thick herbaceous leaves like hostas, lillies and iris. Use a slug and snail bait around these plants, especially when there is new fresh growth around. We recommend Tui Quash because it is safe to use around kids, pets and other wildlife.
Water features and suitable damp loving plants often make an ideal combination. They are ideal in shady, damp and cool areas as many water plants do best in part shade. Water features create a gentle sound, extend your garden interest and can draw attention to the often forgotten damp corners of your garden.
This ‘How To’ Guide has been produced to provide basic information and our experienced staff are available to answer any questions that you may have. Because this guide is of a general nature, neither Palmers nor its staff are responsible for the application of the information, as the contents may need to be modified for individual projects and site applications.