The Best Winter Hardy Pond Plants Species (Top Cold Weather Picks)
An essential component of aquatic ecosystems, including your garden pond, are plants! They aid in oxygenating the water, filtering out pollutants and excess nutrients, and provide shade, food, and shelter for your pond’s inhabitants. However, different species are of course best adapted to certain climates, and depending on your location you may need to choose plants that are able to survive winter. To determine which plants will do best in your region, you should consult a plant hardiness zone map.
In short, there are 13 different hardiness zones in the United States, and each zone is broken up into two sort of sub zones (A and B) to account for slight variations within each zone. Zones 1a to 7a experience average annual extreme minimum winter temperatures as low as -60 degrees Fahrenheit to 0°F, respectively (essentially, these zones often have winter temperatures below zero degrees), while zones 7b to 13b range from 0 to 70°F, respectively (with 7b being 5 to 10°F and 13b ranging from 65 to 70°F). An image of the US pond plant hardiness zones can be found below (click for larger size):
Similarly, Europe has 8 hardiness zones, and Canada has 10 – this is due to the absence of any subtropical zones in these regions, like those found in portions of the southern United States. After determining which hardiness zone you’re in, you can then conduct some simple research to figure out which plants are best for your pond and climate! For example, if you live in zone 3 you certainly wouldn’t want to attempt having tropical plants in your pond unless you are able to move them indoors for the winter (which can be a hassle to do, might be hard on the plants, and could also cause stress to your fish as part of their habitat is being removed).
Benefits of Cold Weather Pond Plants
If you live in a cold weather zone, having plants that are either well adapted to the cooler climate, or are perennial and thus return year after year, will provide a variety of advantages. Economically, you won’t have to spend money replacing a bunch of plants in the spring. They’ll also provide water filtration and oxygenation year round (this is especially important in winter, as ice and snow can lead to a decrease in dissolved oxygen levels in the water).
In addition, they won’t die off and therefore won’t deplete oxygen, add nutrients to the water, and won’t create extra work for you having to clean them out of your pond and filters after they die. They’ll also provide beneficial habitat and possibly some food for your fish throughout the winter, depending of course on both the plant and fish species.
List of Winter Hardy Pond Plants (Cold Weather Species)
Here we will cover some of the best floating, marginal, bog, and submerged pond plants for regions that experience cool or cold winters.
1) Water Lilies (Nymphaeaceae nymphaea)
This particular genus (nymphaea) of water lilies is well adapted to cooler/cold climates (typically zone 3 and warmer). With thick rhizomes that are able to subsist in substrate throughout winter and resprout new lilies the following year, hardy water lilies are floating plants that make an excellent choice for cold weather ponds. Their broad leaves provide protection from both the elements and predators, while their long stems and extensive rhizomes are nibbled on by some fish and their flowers are valuable to pollinators. However, because of these thick rhizomes, water lilies are able to grow quickly and can both overtake a pond and be difficult to get rid of. You’ll have to either regularly cut them back, or dig up some of the rhizomes in the spring before they sprout. Alternatively, you could plant them in pots placed on the bottom of the pond that will limit their spread.
2) Water Hyacinth (Eichhornia crassipes)
Water hyacinth is a resilient, highly adaptable free-floating plant that is well suited for both cold climates as well as those near the equator. Many fish like to munch on hyacinth, but that’s often considered beneficial because of this plant’s ability to reproduce and disperse quickly. Because of their hardiness, water hyacinth are exceptionally easy to have and require very little care, other than having to potentially manually cut them back to prevent overcrowding if your fish aren’t eating enough of them to keep their growth in check.
3) Hornwort (Anthocerotopsida)
Also considered to be one of the most effective oxygenating plants, hornwort is a submerged plant that will also stay green throughout winter in most zones, providing oxygen and shelter. It’s not generally browsed on by fish, nor does it reproduce overly quickly, so you’ll have little to worry about in terms of care of maintenance with this plant, during winter or otherwise. They’ll either float freely about the pond, or you can weigh them down with small weights so that they stay put and don’t wind up in your filters.
4) Frogbit (Hydrocharis morsus-ranae)
A floating plant with heart shaped leaves that resemble miniature water lilies, frogbit has evolved a unique and effective method of overwintering. As temperatures begin to cool toward the end of summer, frogbit will develop structures called turions, or buds, that drop off of the plant and sink into the substrate at the bottom of the pond. These buds will remain protected through winter by the mud or other substrate, and are able to give rise to as many as 10 new plants the following season that can cover over a square meter of area per bud. With this in mind, you may want to remove some of the buds to prevent them from taking over your pond, or manually remove some of the new growth in the spring. In addition, in some areas frogbit is considered invasive, and so you should check online to make sure that you can legally have it in your area, as well as take precautions so that it doesn’t spread into natural areas where it can wreak havoc.
5) Horsetail (Equisetum)
Horsetail, also known as scouring rush, is a prehistoric plant that’s been around for many millions of years. As such, it should come as no surprise that these plants are well equipped to persist through winters as harsh as zones 3 and 4. They’re considered marginal, preferring to grow either in damp soil or water that is only a few inches in depth. Like water lily, horsetail also has rhizomes. This is how they’re able to overwinter, as the main portion of the plant will die off while the rhizomes sit dormant in the ground or the bottom of your pond, giving rise to new growth the following season. Horsetails have native species on every continent except Antarctica, and so they generally don’t grow out of control like an invasive species would. If you do find them spreading a bit more than you’d like, you can always pull up some of the rhizomes – they’re not as thick or matted as that of water lily or cattails, so it shouldn’t be as difficult to remove them. In addition, their segmented anatomy makes them quite adept at filtering water.
6) Water Hibiscus (Hibiscus coccineus)
Also known as swamp hibiscus, this plant is classified as a bog plant that prefers to grow either in saturated soils or a couple inches of water. Water hibiscus has large, dramatic flowers that are typically red, pink, white, or some combination thereof. They provide shade (and therefore temperature regulation) along the edge of the water, as well as some protection from predators, while their striking flowers attract local pollinators. As a perennial plant, coccineus will die off each fall, but will sprout again in the spring via seeds that have been known to survive winters that reach as frigid as -30°F (zone 4).
7) Water Plantain (Alisma paviforum)
American water plantain, is a marginal plant with large, oval leaves, long stems, and very small pink or white flowers. Also a perennial, paviforum will die off in mid to late autumn, though its seeds will persist through winter and are hardy in zones 3 through 9. Additionally, the submerged portions of the plant provides habitat for aquatic invertebrates, which are in turn eaten by fish, frogs, birds, snakes, and so on. While aquatic baby’s breath specifically encompasses only American water plantain, the common water plantain has similar characteristics and has native species throughout much of the world, including North America, Europe, and portions of Asia and Africa.
8) Water Soldier (Stratiotes aloides)
Another floating plant, water soldier is also known as water aloe or water pineapple due to its protruding, long spiky leaves. Though they look rather like a tropical plant, water soldiers have also developed an interesting adaptation to survive winters, even those that delve into the negative digits. As water cools in the autumn, the main leafy portion of the plant becomes saturated with water, causing the plant to lose its buoyancy and sink to the bottom of the water, where it’s able to survive ice so long as the water is at least a few feet deep. However, water soldier is native only to Europe and Asia. The other native plants in these areas have adapted methods of competing with water soldier so that it doesn’t crowd them out. If you live in Canada, water soldier is considered highly invasive and possession of it is prohibited; it’s also invasive throughout much of the U.S., though some states have wild, natural populations and allow it to be used in ponds. In areas where it’s not considered native, local plants have not evolved to be able to compete with it and as such water soldier is detrimental to ecosystem health.