8 Types of Plants Every Water Gardener Should Know

Pond PlantsYou have thousands of plants to choose from when it comes to building your pond ecosystem.

Sound a little overwhelming?

Luckily, most pond plants fall into one of six basic categories: waterlilies, lotus, marginals, submerged, lily-like and floating. You also only need to learn two terms - tropical and hardy - to understand whether your plant will survive the winter outside. Learning these eight words will help you understand what you're looking at when you pick out your first plants.


At a Glance: Types of Pond Plants

  • Hardy plants survive Pennsylvania winters and return the next spring.
  • Tropical plants die in cold weather. You can bring them indoors in the winter, or, like most people, simply treat them as annuals.
  • Waterlilies like to have their roots submerged in deep water while their leaves and flowers float to the surface.
  • Lily-like plants grow in conditions similar to those of waterlilies.
  • Lotus tower above the surface of your pond, showing off their large, colorful flowers.
  • Marginals grow in moist soil, shallow water, streams and bogs.
  • Other plants grow submerged underwater or floating freely on the water's surface.

Hardy vs. Tropical

Think about your regular garden. You have your annual plants - geraniums, petunias, marigolds - that you have to replace every year. Then you have your perennials - lilies, peonies, daffodils - that bloom every spring.

Pond plants aren't much different. Most nurseries classify each of their plants as either hardy or tropical. Hardy plants, like perennials, survive the winter in the climates where they're being sold. Tropical plants, on the other hand, die in cold temperatures - meaning you either have to bring them inside for the winter or plan to replace them next season, the same way you would an annual plant.

Tropical Pond Plants

Pink Spritzer Canna

Pink Spritzer Canna

When it comes to tropical plants, think of Vegas: Flashy, exotic, larger-than-life.

Tropical waterlilies, for example, come in hard-to-find colors like blue and bright purple. They often sport large and unusually shaped blooms that rise a few inches above the water's surface, unlike hardy lilies that just float in your pond. Some tropical waterlilies - so-called night bloomers - even open up in the late afternoon and evening, when their hardy counterparts are sleeping. Some popular tropical waterlily varieties include the multi-toned Green Smoke lily, the night-blooming Trudy Slocum and the bright purple King of Siam, Lindsey Woods and Panama Pacific.

Waterlilies aren't the only place in your garden where you can add some tropical flair. You can also find all kinds of tropical marginal plants to line your pond's borders. Like tropical waterlilies, these plants are usually big and bright. Look at the popular canna family of plants, for example. These exotic-looking flowers stand a few feet off the ground and come in colors ranging from hot pink to electric yellow. Popular varieties include Pink Spritzer Canna, Peach Delight Canna and Lemon Canna. You can also find marginal tropical plants that don't have flashy flowers but still add that exotic touch to your pond. Umbrella palms boast a starburst of bright green leaves, while giant papyrus have delicate grass-like flowers that crown 8- to 10-foot-tall stems.

Hardy Pond Plants

Of course, you don't want to replant your entire pond every year. That's where hardy plants come in.

What qualifies as "hardy" depends on where you live. The United States Department of Agriculture created a handy map that divides the country into 13 numbered hardiness zones. The lower the number, the colder the average annual extreme minimum temperature. Southcentral Pennsylvania sits around Zone 6.

Gardeners use the USDA Plant Hardiness Zone map to describe the climates where specific plants can survive outdoors year-round. If you live in Pennsylvania, you want something that is hardy to Zone 6 or lower if you want it to come back the following year. A plant that is only hardy to Zone 8, on the other hand, needs to either come inside or be treated as an annual.

Note that not all "hardy" plants will survive all winters. Extreme cold can kill any plant. You can increase the likelihood of your plants living to see spring by looking up winter care instructions and performing the appropriate maintenance in the fall.

Lilies, Lotus, Marginals & More

Now that you know how to find the best plants for your climate, let's talk about where you're going to put all these aquatic beauties. Some plants like their roots submerged in the deepest part of your pond, while others thrive in the nutrient-rich soil along the edges. Others like to sit in just a few inches of water, and some like to float freely on the surface.

The Deep-water Showoffs: Waterlilies and Lotus

Mrs. PDS Lotus

Mrs. PDS Lotus

Let's start with the plants that really set water gardens apart from regular backyards: waterlilies and lotus.

Both of these aquatic staples thrive with their roots submerged in the deeper parts of your pond - usually anywhere from 8 to 30 inches for waterlilies and about 2 to 12 inches for lotus, depending on the size of the plant. Both waterlilies and lotus can do well in a pot set at the bottom of the pond or planted in a designated pocket. You can also grow lotus in a container placed on a deck or patio.

Waterlilies' leaves and flowers float on the water's surface, providing shade for the fish underneath them and shelter for bugs and frogs light enough to walk on top of them. While most waterlilies bloom during the day and close at night, some tropical varieties prefer to show off their colors in the late afternoon and evening.

Lotus are arguably the showiest pond plant. Lotus stalks can grow several feet over the water's surface, and their large flowers - often pink or white in color - become the focal point of any pond. All of the lotus varieties we sell at Splash are winter hardy in Pennsylvania, meaning you can look forward to watching your lotus bloom and grow every year.

The Marginals: Shallow-water, Stream and Bog Plants

Pickerel Rush

Pickerel Rush

Lots of aquatic plants love the nutrient-rich water around your pond but can't quite hang in the deep end with the waterlilies and lotus. We call these plants marginals.

"Marginals" is a broad term that describes a massive range of plants that live in the moist soil around your pond, submerged under a few inches of water or tucked into the rocks around your stream. Some marginals flower, while others simply provide lush greenery. Some marginals grow several feet high and can do OK with their roots planted in deeper water, while others will drown in anything wetter than moist soil. Some need more-or-less stagnant water, and others need the flow of nutrients that comes from a running stream.

Marginals include such a wide range of pond plants that we can't make too many generalizations about the category. For instructions specific to your plant, you'll need to check the tag that comes with it or look it up in our online learning library. 

Everything Else: Lily-like, Submerged and Floating Plants

Water Hyacinth

Water Hyacinth

So we have the waterlilies and lotus that thrive in deeper water, and the marginals that hang out in the moist soil or shallow water. That leaves a few plants that don't fall into any of these categories: the lily-like, submerged or floating.

Lily-like plants act, like the name implies, a lot like waterlilies but aren't technically part of the waterlily family. Spatterdock is one of the most popular lily-like plants and is often sold alongside true waterlilies. This plant has large green leaves that either float on the water's surface or sit slightly above it. While it does bloom like a waterlily, its yellow flowers' shape is distinctly different from that of actual waterlilies'.

There's something else lurking in the deep alongside the waterlilies: submerged plants. These bottom-dwellers live almost completely underwater, sometimes as far as 10 feet deep, with the occasional small flower poking its head above the surface for pollination. You might recognize some of these plants - like anacharis and hornwort - from indoor aquariums. While certainly not necessary for an outdoor pond ecosystem, submerged plants can help keep algae at bay and provide a place for fish to spawn. They're also popular in warmer climates, where they fill the algae-fighting shoes of prohibited floating plants.

The floating plant category includes water hyacinths and water lettuce, both of which are popular in Pennsylvania ponds. These plants float on the surface of the water, with their roots dangling beneath them. The fact that they suck nutrients directly out of the pond makes them a great tool for fighting algae. Floating plants are also probably the easiest plants to add to your pond: Simply grab a few and plop them where you want them, either in the pond or above the waterfall. Some floating plants, like water hyacinths, reproduce rapidly, meaning you'll have to thin them out if they start to take over your pond. Water hyacinths and water lettuce are illegal in some states because of their invasive tendencies, so check before you buy. (These plants are legal in Pennsylvania and Maryland).

Variety is Key

So what kind of plant is best for your pond? The short answer: All of them.

Each type of plant in your ecosystem pond takes a different kind of nutrient out of your water. A blue plant will take up one kind, while a red one will eat another. A floating plant will absorb a different kind than a marginal one will. Algae can't survive if other plants are taking all of the nutrients out of the pond, so the more and wider variety of plants you have, the clearer your water will be.

Learn More

Want more pond plant know-how? Check out our online Splash Plants learning library for information on more than 100 varieties of waterlilies, lotus, marginals and more. Just follow the link or scan the QR code on your Splash Plants plant tag.

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