The Ultimate Guide – Rain Gardens in Auckland

Tips, Tricks, and Construction of Rain Gardens with Advice on Plant Selection

Shorten this take-out pun about the splash, and make it trustworthy, fun, yet in-depth: Looking to make a splash with your backyard landscaping? Consider a rain garden! Not only do these unique gardens add a pop of colour to your outdoor oasis, but they also play a critical role in preventing flooding in Auckland.

But what is a rain garden, you may ask? The purpose of the plants in a rain garden is to absorb the excess water that collects in the garden. When it rains, the water collects in the garden and slowly filters into the ground instead of overwhelming nearby storm drains and causing flooding.

So, not only are rain gardens practical, but they’re also quite beautiful. They offer an eco-friendly solution to drainage problems and provide a home for various stunning plant species.

If you’re looking to construct your rain garden, fear not! We’ve got you covered with our ultimate guide to rain gardens in Auckland. We’ll cover everything from selecting the ideal location to choosing the best plants for your garden.

What precisely is a Rain Garden?

Rain Garden” refers to a modest trench dug into the earth. That is designed to capture and absorb rainwater from roofs, driveways, and other surfaces. The plants in a rain garden are carefully selected for their ability to thrive in wet and dry conditions and absorb and filter water.

The idea behind a rain garden is to create a self-sustaining, natural system that helps prevent flooding, erosion, and pollution while providing a habitat for wildlife.

The benefits of having a rain garden in your garden are many. For one, rain gardens can help prevent flooding by absorbing excess rainwater and allowing it to percolate slowly into the soil.

They can also help reduce erosion by slowing the water flow and allowing it to seep into the ground. In addition, rain gardens can help filter out pollutants such as fertilisers, pesticides, and motor oil from the water, which helps protect the environment and our waterways.

Explanation of a Rain Garden’s Operation

sgPUB. (2022, May 23). How Rain Gardens Work [Video]. YouTube.

Rain gardens use the natural properties of soil and plants to capture and absorb water. The plants in a rain garden are carefully selected for their deep roots, which help to create a sponge-like effect in the soil.

As rainwater collects in the garden, it slowly filters into the ground, where the plants and soil absorb it. This process helps to recharge groundwater supplies and reduce the amount of runoff that ends up in storm drains and waterways.

Overall, a rain garden is a simple yet effective way to manage stormwater runoff and prevent flooding in your garden. By creating a self-sustaining, natural system that uses the power of soil and plants to absorb and filter water, you can help protect your property and the environment.

Where to Place a Rain Garden?

Choosing the right location and size is crucial to ensure the effectiveness of rain gardens. Several factors must be considered when selecting the ideal location for your rain garden in New Zealand.

The rain garden should be located downhill from nearby buildings to capture and infiltrate rainwater runoff. The type of soil in your location is another critical factor to consider. The soil should be permeable enough to allow water to penetrate but quick enough to drain. Sun exposure is also essential when selecting a location for your rain garden.

When determining the ideal size of the rain garden, a general rule is that the garden should be about 20% of the size of the impervious surface draining into it. However, specific conditions in your location, such as rainfall patterns and soil type, can affect the ideal size of your rain garden.

It is important to note that building a rain garden requires proper construction techniques to ensure its effectiveness. The excavation should be to design depth, avoiding compacting the earth, and geotextile side walls and base of the rain garden excavation. The right under drainage system and proper drainage material, such as gravel, is also crucial.

In summary, the success of a rain garden depends on selecting the right location and size. Consider your location’s topography, soil type, and sun exposure when choosing a site, and ensure that the garden’s size is proportional to the amount of water it will collect.

With proper construction techniques, you can create an eco-friendly solution to drainage problems that benefit your property and the environment in New Zealand.

How to Build a Rain Garden?

Rain gardens are a fantastic way to manage stormwater runoff from your property in an environmentally-friendly manner. Building a rain garden can help you reduce the amount of runoff and prevent pollutants from entering nearby bodies of water. Here are the steps to create a rain garden and the tools and supplies needed to complete the project.

Step-by-step instructions for building a rain garden

Step 1: Plan and Design

First, choose a location where water naturally collects, such as at the bottom of a slope or near a downspout. Keep the garden 10 feet from your home’s foundation, septic system drain fields, and well heads. Use a shovel and a leveller to check the area’s slope and ensure the garden is graded correctly.

Step 2: Excavation

Dig out the area you have marked for your rain garden. Ensure the garden is about six inches deep and has a slight slope to help water flow towards the centre. Use a sod cutter, shovel, or soil excavator to remove the sod and soil, and then add a layer of sand or gravel to the bottom of the garden to help with drainage.

Step 3: Amend the Soil

Mix the excavated soil with compost to improve drainage and nutrient levels. Ensure that the earth is level and evenly distributed in the garden bed.

Step 4: Plant Selection

Select native plants, such as shrubs, perennials, and annuals, adapted to your climate and can thrive in wet soil conditions. These plants will also help filter any contaminants from the runoff. Be sure to choose plants that vary in size and bloom time for a diverse and attractive garden.

Step 5: Mulch and Maintain

Mulch should be applied to the soil’s top layer to aid with water retention and weed control. Be sure to water your rain garden regularly until the plants become established, and continue to monitor the garden for any maintenance needs, such as pruning and weeding.

Tools and Supplies

You will need the following tools and supplies to build a rain garden:

  • Shovel or soil excavator
  • Sod cutter
  • Leveler
  • Sand or gravel
  • Compost
  • Native plants
  • Mulch
  • Watering can or hose
  • Pruning shears
  • Weeding tools

Additional Recommendations

Consider the following additional recommendations to build and maintain a successful rain garden:

  • Choose plants that can tolerate a wide range of water levels, as the water in a rain garden can fluctuate.
  • Consider installing an overflow system or an underground pipe to prevent flooding and damage to your property.
  • Regular maintenance is crucial to keeping your rain garden healthy and functioning correctly. This includes trimming, mulching, and weeding as needed to prevent clogging and keep your plants healthy and thriving.

Following these steps and recommendations, you can build and maintain a beautiful and functional rain garden that will benefit your property and the environment.

Selecting Plants for a Rain Garden

Rain gardens are designed to collect rainwater runoff from your property, reducing stormwater pollution and protecting local waterways. Native plants are well-suited for rain gardens because they have evolved to thrive in local climate and soil conditions. 

The reasons why native plants are fantastic in a rain garden:

  • Adapted to local conditions: Native plants have adapted to local climate and soil conditions, making them better suited to thrive in the specific requirements of a rain garden.
  • Help to manage stormwater: Native plants can help to reduce stormwater runoff by absorbing rainwater, reducing erosion and filtering pollutants.
  • Provide habitat for wildlife: Native plants support local ecosystems and provide habitat for birds, butterflies, and other wildlife adapted to the local environment.
  • Low maintenance: Native plants can adapt to the local environment and require less water, fertiliser, and pest control than non-native plants, making them a low-maintenance option for a rain garden.

When it comes to the best plants to grow in Auckland to resist heavy rain, it’s essential to select plants that can tolerate wet and dry conditions. 

Some native plants that grow well in rainy places in New Zealand include:

Kowhai (Sophora species): A small tree or shrub with bright yellow flowers tolerating wet soil conditions.

Harakeke (Phormium tenax)also known as New Zealand flax, is a hardy plant that can tolerate wet soil conditions.

Harakeke is one of the best native plants for rain gardens

Harakeke is one of the best native plants for rain gardens. Photo by

Toetoe (Cortaderia species)Toetoe is a tall grass with long, feathery plumes that can tolerate wet soil conditions.

For plants that absorb the most water in New Zealand, consider species that are adapted to wet soil conditions, such as wetland plants like raupo (Typha orientalis), harakeke (Phormium tenax), and Manuka (Leptospermum scoparium).

Finally, for plants that grow well in clay soil with inadequate drainage in New Zealand, it is essential to select plants that can tolerate those conditions. 

Native plants adapted to grow in wet soils, such as Cabbage trees (Cordyline australis), are good options.

Rain Garden FAQs

Are rain gardens worth it?

Investing in a rain garden may be worthwhile if it is built in the correct spot and populated by the right plants. These gardens remove pollutants and moderate stormwater flows, replenishing freshwater and making it aesthetically beautiful. 

Plants and soil mix filter stormwater, trapping dangerous elements before releasing them into the ground, pipelines, drains, streams, and sea. There are drawbacks. Due to basin runoff, poorly constructed rain gardens, in contrast, may cause overflowing and floods. Unplanned ponds may exacerbate erosion rates. 

Yet, properly built and planted with the correct grasses and floral perennials, rain gardens may reduce property runoff inexpensively and attractively. Rain gardens shelter and feed insects and birds. Hence, rain gardens are profitable investments if planned and implemented correctly.

Can you put a rain garden next to a house?

When considering building a rain garden near a house, it’s crucial to evaluate several factors to ensure the garden doesn’t cause water damage to the home. It’s recommended that the rain garden be at least 10 feet away from the house to prevent water from penetrating the foundation. 

It’s also essential to place the garden away from septic systems rather than in areas with standing water. Porous soil should be used for drainage, and the garden should be built in a location where it can collect runoff from impervious surfaces like roofs and driveways. It’s also advised to allow at least a foot of space around the foundation to prevent moisture buildup and insect infestations. 

While some argue that a rain garden can be built adjacent to a home, proceeding with caution and sound design is critical. The depth of the rain garden should be sufficient to allow water to permeate the soil slowly.

Is collecting rainwater illegal in New Zealand?

Collecting rainwater is a common practice around the world, and in New Zealand, there is much debate over the legality of rainwater collection. However, the good news is that there is no prohibition against collecting rainwater in New Zealand, and there are various benefits to doing so. 

For instance, rainwater collection helps to conserve water and reduce utility bills. Additionally, it can serve as a source of emergency drinking water. It is important to note that tanks with less than 35,000 litres of capacity do not require a building permit, but any larger tanks do require a permit. 

As with any water source, it is crucial to ensure the water is good to drink, and it is best to avoid drinking it without filtration. While there is no blanket ban on rainwater collection in New Zealand, you must check with your local authorities to ensure you comply with regional rules and regulations. 

As a responsible citizen, it is essential to consider the potential environmental and social consequences of improper rainwater collection.

No More Floods: Tips to Avoid Water Pooling

If your yard gets bogged down, various choices exist for addressing and preventing the problem and complementing your rain garden.

Following is a bucketful of tricks to keep your property high and dry:

  1. Improve Soil: Hydrated lime, compost, and vigorous aeration can help dry wet soil. Turning the damp ground and adding hydrated lime and compost can help absorb water and spread it throughout the garden.
  2. Clear Drains and Gutters: Regular cleaning of drains and gutters will prevent clogs and maintain water flow.
  3. Water-Loving Plants: Plant water-loving plants like flax, ferns, hostas, irises, and astilbe to help your garden absorb excess water.
  4. Use a Water Butt: Collect rainwater in a water butt to avoid garden flooding.
  5. Level Your Lawn: Leveling your lawn will prevent water from gathering and flooding. A landscaper or rake can level your grass.
  6. Build Drainage Channels: Effective channels need proper design and installation around parking spaces to prevent pooling.
  7. Spread New Topsoil: Fresh topsoil helps enhance drainage and reduce pooling. It may also level the soil, preventing water from collecting and flooding.
  8. French Drain: A gravel-filled ditch with a perforated PVC pipe, the French drain quickly drains water.
  9. Grassy Swale: A long, thin trench can be dug by hand in a day or two to drain water and reduce soil erosion.
  10. Valley: A pipeless French drain using gravel or stone trench to divert water.
  11. Trench Drain: A gravel or crushed stone-filled trench drain with a grating to let water into the trench but keep debris out.
  12. Dry Well: A covered pit that collects water from French drains, downspouts, and other drainage systems. Water seeps into the earth from the gravel-filled well.
  13. Perforated Drain Pipe: A gravel-filled trench holds a perforated drain pipe to divert water. Water flows through tiny pores in the line to prevent water accumulation.

Grab your garden tools, and let’s get messy with appropriate drainage maintenance! Because preventing drainage repairs is usually better than tossing money down the drain.

Green Up Your Space: Top Places to Buy Plants and Landscaping Supplies in West Auckland

If you’re looking for the best local places to purchase plants and landscaping supplies for a rain garden in West Auckland, then you’re in luck! There are several fantastic options available in the area that offer quality products and excellent customer service.

One of the top places to check out is Gordons Nurseries, known for its eco-sourced New Zealand native plants. Located just five minutes from Titirangi Village, this nursery stocks many trees, shrubs, ferns, bromeliads, and indoor plants. They also offer landscaping services for professional help with your rain garden project.

Another great option is Signature Plants, which has two wholesale nurseries in Dairy Flat and Oratia, Waitakere City. With a team capable of fulfilling larger contract growing orders, they have an excellent range of plants and can accommodate landscaping projects of any size.

If you’re up in Waimaku, West Auckland, then Awa Nursery is worth visiting. Open seven days a week, they have a vast selection of plants in various sizes, and they grow 85% of what they sell themselves. They have many options with at least 100 plants of most lines at any time.

And finally, The Landscape Yard is an excellent addition to the family business and offers a broad range of landscape products with a creative twist.

Meanwhile, Central Landscape Supplies is New Zealand’s largest landscape supplies group and has an extensive range of products from Drury to Warkworth, including Waiheke Island.

They also prioritise using products derived from recycling, composting, and reusing organic material to be environmentally friendly.

Wherever you go in West Auckland, you can get the plants and landscaping materials you need to make a beautiful and practical rain garden from one of these businesses.


And there you have it, folks – the ultimate guide to rain gardens in Auckland! With our tips and advice, you can build a beautiful and practical rain garden that helps with drainage and flood issues and benefits the environment.

So, what are you waiting for? Let’s get planting and start splashing around in our rain gardens! And remember, if anyone tries to rain on your parade, tell them to leaf you alone.

Thanks for reading, and happy gardening!


Rain Gardens Construction guide: Auckland Council []. (n.d.). Rain Gardens Construction Guide (STORMWATER DEVICE INFORMATION SERIES).

Quay Street rain gardens -. (n.d.).

Rain gardens / RHS Gardening. (n.d.). Royal Horticultural Society.

M. (2023, February 24). How To Build A Rain Garden – A Complete Step By Step Guide To Make Own Rain Garden At Home. E Home Interior.

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