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Water Plants & Water Features in the Landscape

Water Plants & Water Features in the Landscape

Garden Center Crystal Lake

Water features, ponds and water gardening can add much to an existing landscape. Whether a small container water garden or a large pond, the environmental aesthetics acheived are well worth the effort it takes to get started. A great way to create ambiance and movement in a landscape is through the use of water. Below, we outline a couple different styles of water gardening. Most of these water plants and water garden accessories are typically stocked during the planting season at our garden center and nursery.


Container water gardens are fun because they’re versatile and easy to care for. They do not require mechanical or biological filtration to stay clear and balanced. You can use almost any type of container. There are only a few requirements for a balanced patio pond: water, plants and perhaps a few snails or fish.

Whiskey Barrels

Plants should be left in pots. Water lilies (use only small or dwarf plants) can be 10” to 18” deep. Hardy Marginal or Tropical Marginals can be placed so the top of the pot is 2” or under water. Use bricks or turn pots upside down to achieve desired level.

whiskey barrel water garden


Free-floating water plants are perhaps the easiest and most carefree of all aquatics. What’s even better is that they are among the best filtration plants that you can put in your pond.  Floaters like Water Hyacinth and Water Lettuce shade the surface and absorb nutrients which helps to reduce the incidence of algae in the pond.  Floaters are also great oxygenators and provide shade and protection for fish.     

water lettuce

Care and Maintenance of Free-floating Aquatic Plants

Floater care is minimal.  Remove spent leaves and flowers.  Floaters are annuals, they will be spent after the first hard frost.  Remove them from the pond in late fall and replace them following spring.

Care and Maintenance of True Water Iris

Water Iris require only minimal care during the summer, much like any other water plant.  Fertilize Iris monthly, using 1 tablet per gallon of soil.  Make sure that there is continuous water over the crown of the plant.  Transplant Water Iris during the summer, as needed, and remove spent leaves and flowers.  Deadheading is recommended, since True Water Iris can be prolific self-seeders. 

In fall, Water Iris can be left in their pot in the pond.  Just remove dead foliage after there’s been a frost.  Because Water Iris can withstand a hard freeze, the plants can also be left in the pond during the winter.  Iris are heavy feeders and will require an early start with fertilizer in May, when you should use on tablet per gallon of soil.

True Water Iris are perfect for the natural, earth-bottomed pond.  Simply plant them directly into the pond soil at the proper water depth.  Fertilize them with tablets about once a month, at the rate of 1 tablet for every 10 inches of plant material.  Don’t place the tablet too close to the Iris tuber or it may burn the roots of the plant.

water iris

                                              WATER LILIES

Hardy water lilies require at least 3 hours of sunlight, but prefer at least 5 to 6 hours of sunlight to flower and grow well.  Hardy water lilies have fragrant flowers that open in the morning and close at night.  Each individual blossom on hardy lasts for three to four days, but they will rebloom throughout the season.  It’s important that lilies have still water, they will not survive in a spot that has moving water or water splashing from a fountain or a waterfall.  Hardy water lilies can withstand the cold of northern winters as long as their tubers don’t freeze solid.  They’re hardy in Zones 3 to 11. 

Care and Maintenance of Hardy Water Lilies

Hardy water lilies should be fertilized once per month during the summer using 1 tablet for every gallon of soil.  Remove any spent leaves and flowers.  Transplant a hardy lily during the summer if you think it needs a larger pot.

Fall and winter care of hardy water lilies is also minimal.  Stop fertilizing the plant 3 weeks before the average frost date for your area.  When cold weather strikes and your hardy lily has experienced a hard frost, remove all foliage and flowers down to the soil level in the pot.

When overwintering a hardy water lily, it is important not to let the crown freeze solid - if it does freeze, it probably won’t survive the winter.  If your pond is deep enough that it won’t freeze solid, then simply set the potted hardy lily at the bottom of the pond.  If your pond isn’t deep enough, use a pond de-icer to make sure that the lily doesn’t freeze solid.  If you have the lily in a container garden, remove the pot from the pond or tub and store it in a cool, dark, damp place where it will stay below 40 degrees F.  Make sure that you’ve cleaned the plant by removing foliage and flowers.  In the spring, simply clean up the plant.  Add new fertilizer tablets, one tablet per gallon of soil, and place the pot back in the pond about 6 inches below the water surface when the pool temperature reaches 45 degrees F. Lilies can be transplanted while they are still dormant in the spring before you return them to the pond.


pickerl weed

Marginal plants grow with their crown below the water surface while most of their plant growth occurs above the water.  We’ve classified a marginal as “hardy” if it withstands out cold, freezing Zone 5 winters.  They’re easy to care for and, since they’re perennials, they will come back year after year.  Hardy marginals are well suited for use in a pond or in a container garden on your patio. 

Hardy marginals come in many different shapes and sizes.  Some like part shade.  Most like full sun.  Some are tall and narrow while others are short and bushy.  Flower colors vary, as do leaf shapes and season of bloom.  Planning a garden for hardy marginals is much like planning a herbaceous border.

 Care and Maintenance of Hardy Marginals

Summertime care of hardy marginals is minimal.  Fertilize the plants about once per month using one tablet of fertilizer for every gallon of soil.  Other than occasional fertilizing, all you need to do is remove spent flowers and foliage.

Potted hardy marginals can be transplanted into a larger container if you think they’re starting to crowd out of the pot.  It’s always wise to use pea gravel on top of the soil.  This not only prevents soil loss, it also serves to inhibit your curious Koi from digging up your plants.

In the fall, stop fertilizing hardy marginals 3 weeks before your average frost date.  Hardy marginals should not be transplanted in the fall.  Winter care of hardy marginals is also simple.  Once you’ve had a frost, cut back the foliage on the plant to a few inches above the rim of the pot.  Most hardies can withstand a hard freeze during the winter, so they can stay on their ledge in the pond during the winter without further care or attention. 


Tropicals cover the spectrum of flower color, foliage shape, and plant size.  They’re much like annuals to us northerners, and we have to take special care of them in the winter. But who can complain?  Tropicals grow more quickly than hardy marginals. What’s more, they bloom all summer long and into the fall. Their colors are vivid, and the taller tropical marginals especially have a look that is exotic, and breathtaking.

Care and Maintenance of Tropical Marginals

canna water plant

Cooler weather in the fall, about three weeks before the average frost date in your area, is the time of year when you should stop fertilizing your tropical marginals. As the frost approaches, but before it arrives, bring the plant inside and put in a sunny window, placing its pot in a bowl or tray with a least 1 inch of water.  The plants will do best if the indoor temperature is a least 65 F.  Don’t expect them to put on a lot of new growth. Tropicals are like houseplants during the winter.  They do not actively grow during cooler months when the day length is shortened.  Return the plants to the pond once the water temperature is a least 75 F.  Add fertilizer at the rate of 1 tablet per gallon of soil.  Resist the temptation to return a tropical marginal to the pond when the water’s still to cold and it’s too early in the spring. It’s better to wait a while than risk a cold or freezing night that will stunt the plant’s growth.  Or treat them like an annual and replace each year. 


You may repot aquatic plants for a number of different reasons, for example if a plant has outgrown its pot, or if you want to divide a plant to make more.  First choose the right pot.  You can use an aquatic plant basket or you can use a recycled nursery pot.  Use Ultra Natural Soil Conditioner as a “soil” to give you the weight you need without clouding your pond.  You can also create a mixed “container garden” for your pond by combining different plants in the same container. 

Are you interested in a large scale water feature? Click here to see some of the landscape water feature installations completed by The Barn Nursery's Landscape Design Division.


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