Answers to the most common pond plant questions

small pond with mix of aquatic plants

​     Whether your pond is small or large, your pond will reap big benefits from having water plants!  Aquatic plants clean your water and beautify your pond. Every pond owner dreams of less algae and aquatic plants can help! How do they do this?
     Water garden plants need nutrients just like plants growing in soil so the nutrients floating around in the water are drawn in through their roots.  Nutrients can come from fish waste, old leaves and debris rotting in the water, or minerals present in the water.  Algae, also in the plant Kingdom, need nutrients too.  If your aquatic plants are using the nutrients, less are available to algae.  Fewer nutrients for alae equal less algae growth and cleaner water!

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How many plants does my pond need?

To determine how many plants you need, ask yourself the following questions.

1. How big is my pond? (6x8’, 8 x 11’, larger?)
2. How much sun does it get every day? (You will want to choose plants that have similar sun requirements.)
3. How big to the mature plants get which I like?  (Example- Cana lilies can get tall and wide.  Will that block all views of my pond? Some water lilies can spread up to 8 ft. each!)

Having a variety of marginal plants, floating plants, and submerged plants makes the pond interesting and helps oxygenate the water.  If your pond is small (6 x 8”), 2 or 3 marginal plants, 1 water lily, and 2-3 submerged plants will be plenty.  A design trick is to select small plants for a small pond such as mini cattails or miniature water lilies.
Click here for a handy planting guide with several pond sizes shown: Don’t be afraid to experiment!
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Pond Planting Guide Sample

What kind of plants should I use?

The answer to what kind of plant should I use depends primarily on how much sun exposure your pond gets.  The water garden plants you choose should need about the same amount of sun.  You don’t want a shade plant mixed with a sun lover!  One plant will suffer, one plant will take over.
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​You will also want a mix of floating plants, marginal plants, and submerged plants to oxygenate the water.
Floating plants float on the water.  Common ones are water lettuce, duckweed, bladderwort, water clover, and water hyacinth.

Submerged plants have their roots completely under the water. They are planted right in the pond gravel or in a pot sitting on the pond bottom.  Water lilies, smartweed, and lotus roots come to mind.

Marginal plants are planted so their roots are wet but the stem may or may not be completely in the water.  They are planted in rock ledges or crevasses around the pond edge and are highly effective at framing waterfalls, softening edges, and filtering unwanted runoff from nearby lawns. Mini cattails, arrow root, marsh marigolds, forget-me-nots, cardinal flower (lobelia), and creeping jenny  are examples of marginal plants.

One special note: Some plants are very aggressive in growth and will take over.  These plants can be used but may need to stay in a pot to contain them.  Some plants may be illegal and invasive to native water ways. Here is a list of 10 such plants.  The MN DNR has a list with photos of invasive aquatic plants.

What happens if I have too many plants?

This pond needs a clean out!

​Too many plants in your pond cause problems just like having too few pond plants!  An overgrown pond looks messy and is hard to care for.  Excessive foliage chokes the water preventing correct filtering.  If you have too many plants, so many that you can’t see the water, then it’s time to rip a few out and dispose.  (Remember to dispose non-natives according to the MN DNR rules so you don’t accidentally introduce something into the wild which will become invasive.)

For large plant clumps, remove the clump, cut off unwanted dead or damaged spots and rotten stems.  If you like the plant, save a small but healthy piece and replant it.  If the plant is very aggressive, planting it in a pot which is then submerged will help control future growth.

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How do I care for my pond plants?

 All plants need food, water, sun, and regular trimming to look amazing. If you are not getting many flowers, the plant probably needs a little fertilizer or more sun. Some plants like water lilies and lotus benefit from a slow release fertilizer pellet put in their root zone.

Regular plant trimming removes rotten or damaged leaves. Check your aquatic plants for damage after a heavy rainstorm or windy day, too.  Sometimes the pots get tipped over and just need to be reset.
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If a plant looks yellowish, it may be in the wrong sun exposure.  Shade loving plants bleach out in the sun and will get a “burnt” look on the margin.  Sun loving plants that are in shade will be thin and weak.  Move the plant to a different spot in the pond or try something new!
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Don’t be afraid to experiment!  Gardening, especially water gardening, is fun!  For expert help with your water garden please contact us. If you just don't have the time or desire to get dirty this spring, sign up for a Pond Spring Clean-out! (learn more here...)