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Although it might seem that a garden has a problem with wet soil, it is a fair bet that most gardens that appear wet now are actually fine. In the coming weeks, the odds are that the pattern of steady rain will lift and the excess water in the ground will drain away. Suddenly, it will be possible to cultivate soil, sow seeds and plant trees, shrubs, and perennial flowers, into nicely moist but not damaging levels of water.
But how do you determine whether the soil is poorly drained, or not?
Getting your garden ready
The first action is to dig three to five holes spaced over the extent of the garden. The holes should be roughly the depth of the head of the spade, taking out the soil and setting it to one side. Observe the colour and consistency of texture and structure. The colour of soil is largely determined by the iron salts it contains. Iron in its ferrous state is brown-red, while its ferric state is blue-grey. The ferrous state, being brown, holds more oxygen than the ferric state, which is blue-grey.
Roots of plants need oxygen to function, and if the soil is wet, it pushes the air out of the soil and plants suffer from lack of oxygen and, to a greater or lesser extent, the root systems of susceptible plants may die and rot. Wet soil can have an unpleasant smell, while red-brown soil is sweet-smelling.
Wait an hour or two to see if the water accumulates at spade-depth in those holes. In the meantime, take note of the existing plant species on the site. The presence of numerous tufts of rushes, meadowsweet, yellow flag iris, willow and alder offers strong indicators that the soil is wet. While it is best not to have any water stand in the holes, it may do so for a few days without fear of harm to plant roots. But if water rests in the holes for more than a week, it may be necessary to consider drainage of some kind. In a small garden, this may be just one or two land drainage pipes to allow the excess water to exit the garden.
However, with small gardens, it may be difficult to find an outlet for the water and it may be necessary to dig a soakaway pit. The alternative to drainage is to grow plants that can tolerate water in excess, and this approach can be applied either to small or large gardens, or smaller areas within a large garden, which might be the case in a country garden.
Wildflower lawn
When planting a large garden, choose big plants, namely trees, or keep a large area of grass. Grass will need to be mown as a wildflower lawn, or as a wildflower meadow. If the ground is prone to being wet, it might be difficult to mow as needed. On the other hand, once established over five years, trees can fight their own battles with smaller plants.
While there is a good choice of trees to grow in well-drained soil, the range is limited on wet soil. Alder, grey willow and downy birch are native species well adapted to Irish conditions of soil and climate. There are some foreign species that could be used, such as the taxodium, but these can look somewhat out of place in a rural setting.
As for shrubs, there are not many either. Some kinds of dogwood can be used, also smaller varieties of willow, chokeberry, potentilla and hydrangea. The choice of shrubs is not great for wet ground, but many more kinds can be grown if they are planted on a shallow mound. The mound keeps part of the root system free of excess water and can make the difference in survival. The dimensions of the mound should be 15 to 20cm at the centre to being away at a width of roughly one metre diameter.
Woody species, trees, shrubs and climbers that like wet ground are limited. They include skunk cabbage, candelabra primula, astilbe, Joe Pye weed, summer lobelia, purple loosestrife, yellow loosestrife, arum lily, valerian, meadowsweet and gunnera.
The species that like wet soil make fine big plants and rarely suffer from drought because they are well supplied from the wet soil in which they grow. Most of these plants have large leaves because there is little risk of them becoming dry and shrivelled.
Although most of these plants are native to wet mineral soil, not peaty land, they are often called ‘bog plants’, which they are not. They would be better known as marsh plants, not that it matters enormously, once you are matching wet-ground lovers to the right conditions.
Use only plants that thrive in wet ground and don’t waste time, effort and cash. Work with Mother Nature, not against her. Mother Nature always wins.
Fruit, vegetables and herbs
Control weeds around fruit trees and bushes as weeds and grass reduce growth. Sow vegetable seeds of most kinds if conditions allow and the soil is dry enough to till. Onion sets can be put in now. Potatoes can be planted at any time. Spray apple and pear trees against apple scab disease.
Trees, shrubs and roses
Bush roses and repeat-flowering climbers are growing strongly and should be sprayed soon against blackspot disease. Evergreen trees and shrubs, both broad-leaved and coniferous, can be planted and they will root quickly, but be sure to give a good watering at planting and two weeks later.
Flowers
Gladiolus and dahlias can be planted directly outdoors from the middle of the month. Wait for a while in the colder localities. Lilies can also be potted up for summer flowers. It is really too late to sow bedding flowers because they will flower very late. Instead wait and buy well-grown fresh plants in May.
Lawn
Lawns may need feeding in most cases, unless they are showing green. Mowing should be well under way. Use lawn mosskiller if there is heavy moss growth. If the lawn is to be maintained as a short cut wild flower lawn, do not use fertiliser as it makes the grass grow at the expense of the wild flowers.
Greenhouse and house plants
Sow seeds of sweet peppers and chilli peppers. If there is a delay past early April, it would be better to wait and purchase plants. Feed and water heavily all greenhouse plants, if not already done. Around the mid-month is the time to sow sweet corn and runner beans for planting out at the end of May.
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