Too much water in part of the garden is a problem that affects many gardeners. The problem can be a constant one where it occurs all year round or it may be seasonal. It might be that the septic tank overflow, or the stormwater drains into one corner of the yard resulting in at best moist soil and at worst a complete bog. It may be just a low spot that collects all the water from the surrounding area. Whatever the reason, there are ways of turning a boggy or wet area to your advantage.

Some plants thrive in wet areas, and with the right plants you can still achieve an interesting and attractive garden in a wet area.

What Can Cause Wet Areas In Your Garden?
*Septic runoff can be a problem, particularly in areas with poorly draining soils. Often all you get is an area where the grass or plants always seem to grow more lushly as a result of a plentiful supply of moisture (and nutrients). At times however, you may get a quite boggy patch or line along the septic runoff where little seems to grow. These areas can also be quite foul smelling at times.
*Waste water from your house that is drained into your garden.
*Rising water table (eg: particularly from over irrigation in rural areas) or naturally occuring springs.
*Water from surrounding properties may drain into your garden. This could be naturally occuring or may result from your neighbours diverting water, either intentionally or unintentionally, from their property into yours.
* Low areas or depressions provide a site for water to collect. The water could be from rain water, garden irrigation, etc.

Problems With Wet Areas

  • It is often difficult to get plants to grow. You must choose the right
  • Mosquitos and other annoying insects are encouraged by stagnant and
    boggy areas.
  • The presence of stagnant water can be a health hazard. It can also be
    very smelly.
  • Access is restricted (eg: you can sink into muddy areas)
  • Visually the area may look quite ugly. It may also be quite messy for
    kids and animals (fence off or plant so densely that access is


Wet areas can be overcome in the following ways:

*Prevent or reduce the amount of water reaching the garden. For example septic systems can be connected to the sewerage, blocked drains can be repaired, stormwater diverted elsewhere, etc.

*Fence off, or plant trees and shrubs to screen the area off. This can prevent access to the wet area as well as blocking it off visually. It doesn't however, fix the problem.

*Improving Drainage
For heavy clay soils:
a/ Dig in lots of organic material (eg: mulch or woodshavings). As this
decomposes it improves soil structure and nutrition, helping drainage
as well as increasing the soil's capacity to absorb water.
b/ Add gypsum or Multicrop's clay breaker. These products open up hard
soils allowing better drainage.
c/ Install drainage pipes to take the water away.
For low spots
a/ Dig organic matter into the soil to help absorb excess water and
improve soil structure.
b/ Create a sump pit at the lowest point (see section on creating a sump)

*Raise Levels Or Fill Depressions
Get an earthmoving machine in (or do it by hand if its not a big job) and
change the levels of your property so water drains away instead of
collecting in any one part.
Build a raised garden bed on the surface of the ground.

*Plant With Water Loving Plants
If the area is always wet (eg: from septic overflow):
a/ Use plants which like a continuously wet soil, and do not mind being waterlogged at times (eg: Iris, Papyrus etc). Spread a 4 5cm layer of coarse sand or pebbles over the surface to restrict the growth of algae or any other putrid smells.
If the area sometimes drys out:
a/Create a bog garden by digging out the area, lay a double thickness of black plastic, fill with a good quality, highly organic compost then plant with bog plants.
b/Use plants which tolerate or even like being waterlogged but will tolerate some drier periods.

*Build A Pond And Drain The Surface water Into The Pond

Often the home gardener will find that they have nowhere to drain excess water to. One way of overcoming this problem is to dig a sump. This has proved very effective for disposing of septic runoff. The sump can be located at the end of the septic runoff or elsewhere in the garden away from your house. Try to avoid placing it near other pipes, drains, etc. The technique for creating a sump is as follows:
1. Excavate a hole approximately 1 x 1 x 1.5 metre large. The soil removed
can be used elsewhere or discarded.
2. Fill the hole to within 20 30 cm of the surface with coarse material
such as builders rubble, rocks, gravel, etc.
3. Lay your drains or septic outlet so that they terminate (discharge)
level with the top edge of the gravel.

4. Add a layer of 10 15 cm of sand then fill the remaining part of the hole
up to ground level with a good quality sandy loam or loam soil.
5. Plant lawn or other plants over the excavated area.

What if there are times when it goes dry?
Choose plants which will tolerate this...or else you need to
water...mulching also helps.
Direct sunlight may dry the bog out. Sufficient light is required,
however, for plants to grow. Partial overhead shade may be required;
mulching will also help reduce surface drying out.
Mosquitos and other annoying insects that may breed in the wet areas can
be controlled: by spraying a thin layer of white oil or summer oil on the
surface of the wet area; by improving drainage sufficiently to remove
any free standing water; or by building a pond and installing fish that
will eat any insect larvae.
Algae & moss will thrive and become a problem on wet soil if light is
allowed to reach the soil (Algae needs light to grow). A layer of coarse
sand or gravel spread over the surface will help control algae, as will
spraying it with an iron sulphate solution.
Planting long grasses/reeds, etc. shades the soil and reduces the chances
of algae & moss growing.


Extra Hardy (Tolerating full sun, wind & periods of dry to periods
of flooding eg: dry summers after wet winters).
Acacia floribunda, retinoides
Brachysema lanceolatum
Eucalyptus rubida, viminalis
Grevillea confertifolia, juniperina, laurifolia

Grow Well In Wet, Shaded Places
Kalmia latifolia
Cornus (Dogwood)
Tree Fern (Dicksonia antarctica)
Blechnum sp.
Nephrolepis (Fishbone Fern)
Vaccinium sp. (Blueberry)
Iris versicolor
Lilium canadense
Mentha (Mints)
Myosotis (Forget Me Not)
Oxalis montana (Wood Sorrel)

Tolerating Periods Of Moist To Flooded Soil
(but not drought tolerant).

Tolerates Wet and Polluted Areas
(Where sullage/household waste etc accumulates)
Carex fascicularis
Crassula helmsii
Melaleuca ericifolia
Acacia melanoxylon
Eucalyptus ovata
Callistemon citrinus
Callistemon viminalis

Very Tolerant to Wet soils
(will withstand soil being submerged in water for 3 months or more at a time)
Acer negundo, rubrum, saccharinum
Carya aquatica, illinoensis, ovata
Cretagus mollis
Diospyros virginiana (Persimmon)
Eucalyptus camaldulensis
Gleditsia aquatica, triacanthos
Liquidambar styraciflua
Platanus acerifolia, occidentalis
Populus delatoides
Quercus bicolor, macrocarpa, palustris
Salix alba, nigra
Washingtonia robusta (Mexican Fan Palm)

Ferns particularly tolerant to wet soils
Bechnum siscolor, indicum, minus, wattsii
Cyathea australis, smithii
Cyclosorus interuptus
Dennstaedtia davallioides
Dicksonia antarctica
Diplazium dietrichianum, esculentum
Nephrolepis sp.
Osmunda regalis
Pteris comans, umbrosa


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