How to build a bog garden in 9 steps

A bog garden with purple color flowers

You’ve grown a bit bored with coneflowers, black-eyed Susans and other ordinary perennials in your landscape. Why not create a bog garden, which is easy to install. This article includes 9 steps to build a bog garden in your landscape.

But first, what is a bog garden?

A bog garden is an acidic, spongy area, where the roots of certain plants spend their life wet while the crowns and top growth remain high and dry. As plants die, they sink in the bog garden and decay, forming peat, which has a low pH and is acidic. Peat moss is one of the products made from the peat.

What do you grow in a bog garden? Plants that love moist ground. Also, bog gardens are a perfect place to grow carnivorous plants, which eat bugs. 

Bog gardens frequently are found along the edges of ponds and other bodies of water. In nature, bog gardens formed in pockets of glacier melts.

Your bog garden can be dug anytime you can work the soil. Even though bog gardens are shallow (no deeper than 3 feet), that’s still a lot of soil to dig and move. 

There’s usually no need to rush the project. It’s better to take your time (or hire it out). This step-by-step guide to building a bog garden will get you started.

Different gardening tools like gloves shown in picture
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Tools and materials you’ll need

– Shovel or spade

– Tarp

– Garden rake

– Pool liner

– Peat moss

– Compost and soil

– Sand

– Bog plants

– Access to water

Step 1: Find a spot for your bog garden

A bog garden can be any level space in the landscape that has full sun, or at least six hours of direct sun. Avoid areas with a lot of tree roots. Gullies, drainage ditches, low spots, and the base of a slope are good starting places. 

An area that stays wet will work, too, although not necessary.

Step 2: Decide the size and shape of your bog garden

A bog garden is 2½- to 3-feet deep. That depth allows for future growth of plants’ roots. Too shallow will stunt plants’ growth. It can be however long and wide you want it to be (and have the energy to dig).

The bog garden can be whatever shape you’d like. It can be long and narrow, rounded, half-moon or whatever pleases you and looks good in the landscape. You want the bog garden to fit or look natural with your existing landscape design.

A good size for a beginner’s bog garden is about 16 square feet (or 4 feet long by 4 feet wide). One thing to keep in mind is that a small bog garden will quickly dry out, which adds to maintenance because it will need to be watered.

Step 3: Dig the bog garden  

A person digging soil for garden
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Use a sharp shovel or spade to dig the bog garden. As you dig, place the excavated soil on a tarp or something similar. You will use some of this soil later in the process.

Step 4: Line the bog garden

Use a high-quality pool liner or pond liner to line the bog garden. It’s best to have the sheeting in one piece. Overlapping pieces or seams of liner sheets will leak.

The liner should extend beyond the edge of the dug area by about 12 inches. Hold this sheet extension in place with bricks or rocks while working in the excavated space. This also will allow the liner to settle and shape to the bottom of the bog garden once the soil mix is added.

About 12 inches below the top edge of the bog garden, punch or drill drainage holes every 3 inches in the pool liner. This allows for drainage of overflow, such as from a rainstorm, while keeping the base of the bog garden wet.

Step 5: Fill your bog garden with planting medium

Yes, that’s a fancy word, but in this case, planting medium is not soil. A common mix for a bog garden is 30% coarse sand with 70% peat moss, compost and soil that was dug from the hole.

Thoroughly mix the planting medium on a tarp or something similar. Add the mix to the bog garden in layers about 6-inch deep at a time. Gently tamp down the first two layers, making sure the mix has good contact with the bottom of the liner. Smooth out each layer to even it out across the bog garden hole.

Step 6: Soak the planting medium

Rain water is best, but tap water also can be used. Add water to saturate the mix in your bog garden. Once watered, it’s best to wait a month before planting in your bog garden. Why? You want to make sure the mix settles. If you’re too excited, wait at least a week.

Step 7: Select your bog garden plants

A picture showing many plants of a bog garden
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Looking for the best bog garden plants is what you can do while waiting for the planting medium to settle. You want moisture-loving perennials that can tolerate bog garden conditions – wet roots and acidic, low-nutrient medium. Many native plants fill this bill.

Select bog plants with various forms and textures that will tolerate the water’s acidity. Look for plants that have different seasons of interest, such as spring, summer or fall bloomers. You want plants that are good for your climate and USDA hardiness zone.

Common bog garden plants include sedges, marsh marigolds and sundews. Venus flytrap and pitcher plant are among bug-eating plants that thrive in bog gardens. Carnivorous plants just might inspire your kids (and you) to learn more about other plants, gardening, and horticulture.

Step 8: Plant your bog garden

Just like any garden bed, tall plants go along the back of your bog garden if it will be seen mostly from the front. If your bog garden can be seen from all sides, place tall plants in the center.

Remember to plant similar plants in clusters of three or more for the best visual impact.

Step 9: How to maintain your bog garden

Maintaining your bog garden is super easy. All you really need to do is make sure your bog garden has wet soil. A bog garden must be watered during long dry spells. You do not want the bog garden to dry out.

You can also tidy up plants by removing dead flowers, but it’s not necessary.

Bog gardens are naturally low in nutrients, so you won’t need to fertilize them. The nutrients a plant needs will come from the decaying plants that reach the lower part of the bog garden.

In cold climates, mulch your bog garden with straw, chopped leaves, or other organic matter, to protect delicate plants. You can remove the mulch in spring, or if only a thin layer remains, let it be. Mulch will decompose and eventually fall to the bottom.

FAQ about bog gardens

What kind of wildlife will you see in your bog garden?

Your bog garden will attract frogs, dragonflies, snakes, and small mammals. Flowers will attract butterflies, bees, hummingbirds, and other pollinators.

Do you have to catch insects to feed the carnivorous plants?

No. The bugs are naturally attracted to the plants.

How can you take care of plants if you have to step into a bog garden bed that’s wider than 5 feet?

Install steppingstones to create a path to the plants if you can’t reach them from the edge of the bog garden.

When to call a landscaping pro

You love the idea of a bog garden, but you don’t have the time or energy to DIY, so what do you do? Contact a landscaping professional near you to do the dirty work for you.

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Jo Ellen Meyers Sharp

Jo Ellen Meyers Sharp award-winning garden writer, editor, and speaker. (She speaks at libraries, garden clubs, public gardens, home and garden shows, Master Gardener groups, and horticulture industry events.) Known as a hortiholic, she frequently says her eyes are too big for her yard. She blogs at hoosiergardener.com.