Signs your Rain Garden has an issue. Don't worry, we can help

Signs your Rain Garden has an issue. Don't worry, we can help

Troubleshooting Rain Garden Issues is all part of the Rain Gardeners service!

There are a few signs your may notice that show something is wrong and if your first action is to drop us a line, read no further! Consider the problem solved.

If you're curious about what may be causing pooling of water, runoff, dying plants or more, here's a list of common problems.

Symptom Possible Problems Solution

Stormwater run off is bypassing the rain garden

Local earthworks increasing sediment load to rain garden, blocking rain garden outlets, or raising the surface level of garden.

•        Check surface of the rain garden is below the surrounding area.

•        Remove any sediments and debris from inflow areas and from the surface of the rain garden.

•        Protect rain garden from future construction sediments.

Rubbish and other debris blocking the inflow points to the rain garden.

•        Regularly remove rubbish, leaves, and any other debris from inflow points.


Rain garden is ponding for longer than 24 hours.


Incorrect blend of soil mix.


•        Replace soil mix with the correct rain garden soil mix.

•        Do Ribbon test or percolation test to test soil mix is free draining

The soil within the garden compacted during construction or other activities.

•        Loosen the top 500mm soil by tilling or forking.

•        Discourage vehicle, pedestrian, and bicycle access to the rain garden.

Layer of fine sediment settled on the garden surface.

•        Remove fine sediment layer and turn over the top layer of rain garden soil mix.

•        Protect rain garden from surrounding sediment run off.

Stormwater and/or mulch flowing off the rain garden.


Rain garden filled with too much mulch or soil. •        Remove excess mulch or soil so that surface of ponding area is approximately 200-300mm below the surrounding hard surfaces and overflow.
Overflows or discharge pipes clogged with sediments or debris.

•        Clear overflow and discharge pipes.


Planting or rain garden soil mix clogged.


•        It may be necessary to remove some of the rain garden soil mix and replace with fresh rain garden soil mix.
Sulphur smell coming from the rain garden. Plants and soils lacking oxygen. Organic material rotting in the garden.

•         Inspect rain garden after rain event to check garden drains within 12 to 24 hours.


The underdrain is clogged, and water is not properly draining out of the garden.
Erosion and gouging occurring within the rain garden

Kerbs and other hard structures channelling stormwater flow. (Rain gardens require an even sheet flow of water to operate effectively.)

Inflow points are too concentrated.


•        Create openings in the kerb to increase number and width of run off points, or replace kerbing with a different design (e.g., kerbing slightly raised off the ground).

•        Increase kerb opening size by cutting kerbs or replacing with different design.

•        If this is not possible install riprap (i.e. stones set into concrete) at the inflow point to spread flow and reduce erosion.

Plants are stressed or dying. Symptoms may include yellowing of leaves, unseasonal leaf fall, wilting. Plant varieties selected for rain garden are unsuitable for the location and/or extreme wet/dry conditions.

•        Select plants appropriate for the location (e.g. full shade, partial shade, full sun, etc.).

•        Due to their hardy nature, native plants are recommended

Ponding or excessively long periods of flooding cause plants to become stressed and die.

•        Inspect rain garden after rain event to check garden drains within 12 to 24 hours.

•        See above solutions for rain garden ponding.


The plants poisoned by run-off from a hazardous spill (fuel, paint, oil, etc) Pollutants accumulated in the rain garden reached a toxic level for plan.

•        Check soil and mulch for evidence of heavily polluted run off (e.g. rainbow slick, coloured mulch, etc).

•        If contamination is extensive, clean out rain garden soil mix and replace fresh soil and new plants.

•        See construction guide for instructions.

The plants dehydrated from extended dry conditions.

•        Newly established plants need watering.

•        Check soil moisture content and water plants if dry.

•        Establishing plants need watering in dry weather conditions.

Plants stressed due to attack by plant pests or diseases. Pests may include insects or animals.

•        Check for leaf damage or pests and consult gardening manuals or a garden centre for the best treatment.

•        Stressed plants need replacing with healthy variety or pest-resistant species.

Rain garden soil mix compacted.


•        Loosen the top 500mm of soil by tilling or forking.

•        Do not allow vehicle, pedestrian, and bicycle access to the rain garden.


Back to blog