Water Plants For Ponds And Bogs

by Ann Savannah, CAS

originally published in The Calquarium Volume 42, Number 11, July 2000

When we think of a backyard pond the first few images that pop into most of our minds are those of fountains and fish, usually a goldfish. I think these images must come from viewing too many water features in restaurants, garden centers, and public gardens. We also visualize their bottoms covered with copper pennies, nickels, dimes and assorted small pebbles and toys. These same ponds are also surrounded by potted tropical plants and some even have fake plastic plants "growing" out of the water. But I think we can do much better and create a pond that comes much closer to nature.

Plants that grow in water come in all sorts of shapes and sizes. Many of them flower and most produce interesting leaf shapes. Recently the gardening world has seen huge growth in the popularity of water features from tiny tabletop fountains to very large backyard ponds. The overall benefit from this interest is the increased availability of products: in equipment, hardware, plants, fish, and ornaments, there is an almost overwhelming choice. The problem gets bigger when we have to try and decide what kind of water feature we want to construct: Small? Large? Fish? Plants? I know some people who just gave up, bought a book, and just looked at the pictures. Some even put the scanned pictures on their computer as wallpaper.

My focus in this essay isnít on the actual pond or the fish but on what you can put in your pond that takes little care, no daily feeding, and provides an summerís worth of interest. These are water plants, and I confess absolutely my most favorite part of a pond.

Water plants can be divided into many different groups based on their characteristics; my two basic groups are: hardy (meaning they will live through our winter) and not hardy. The "not hardy"s include all tropical/exotic water plants, all annual water plants, and what I call the iffies.

But probably the most useful way to group water plants is by water depth, or how much water they will tolerate above their crowns (the growing point where the leaves emerge). These groups are:

Submerged: plants that grow below the surface of the water, and can be rooted or free floating. Sometimes called oxygenators; e.g. hornwort

Floating: free floating plants whoís leaves rest on the surface of the water and whoís roots hang in the water column; e.g. duckweed.

Rooted Floating Leaf: rooted plants (deep or shallow) whose leaves float on the surface of the water; e.g. water lily

Emergent: rooted plants with crowns above the water surface and leaves that donít float; e.g. bulrushes

Marginal: plants that grow at the pond edge in wet boggy soil and can tolerate some water over their crowns during the spring; e.g. marsh marigold

Before going to a greenhouse be sure to have the following questions settled in your mind, there is nothing worse than coming home with more plants than water and having to frantically dig more ponds or run to Home Depot to clean them out of rubbermaid containers.

How big is my pond? Is it a small rubbermaid container (or in my case several cat pans), a deck sized Ĺ whiskey barrel, a preformed drop in pool with narrow plant ledges, or a large lined pond with lots of room?

Is it located in the full sun or shade?

Are there fish? Minnows, goldfish, or koi?

Is there still water or moving? Fountain or circulated?

Be aware of the following: fish like to eat plants. Koi in particular will demolish plants: potted ones are their favorites. Fish also need cool water for oxygen levels to remain safe, while water lilies like very still and warm water. Warmth, sunlight, and fish poop make for great algae growth, especially hair algae (the bane of most ponders). Consider also that a pond without at least some fish will be a haven for mosquitoes

Here is a list of some water plants I grow. Not all of them are hardy or native but are instead just plain fun to have for flowers or interesting leaves.

Submersed

Hornwort (Ceraphyllum demersum): not rooted. Look for nice green, loose bunches, any with brown stems are dying and bunches with very tightly held leaves never seem to survive long after being bought. I think this has something to do with what stage of cold dormancy they are experiencing. Not winter hardy if frozen solid.

Canadian Pondweed (Elodea canadensis): best if rooted. Great for ponds without koi, or better yet in a phytofilter (a plant filled pond used as a natural filter). Native, but not winter hardy if frozen solid.

Bladderwort (Utricularia vulgaris): rooted or not. Sends nice yellow snapdragon like flowers above water surface. It is carnivorous, as the little bladder parts eat infusoria, Daphnia, and fry. Native and winter hardy.

Floating

Duckweed (Lemna minor): a necessary evil, provides food for koi, shade at the surface of the pond (less algae), lessens water evaporation, and sucks up nutrients. Native and hardy

Ivy-leaved duck weed (Lemna trisulca): free floating delicate duckweed. Native and hardy.

Azolla (Azolla caroliniana): same as duckweed, but itís a fern, and not native and not hardy.

Frogbit (Limnobium spongia): a nice free floating or partly rooted plant. Same usefulness as duckweed, but sometimes has tiny bottlebrush white flowers. Make great landing places for bees, dragonflies, and other critters. Not native and not hardy.

Water Lettuce (Pistia stratiodes): make nice velvety green clumps of leaves like floating butter lettuce. Sometimes has tiny white flowers. Needs warm water. Hates cold. Sucks up lots of nutrients. Not native and not hardy.

Water Hyacinth (Eichornia crassipes): beautiful clumps of dark green leaves, wonderful lilac flowers. Temperamental: likes full sun and very warm quiet water to bloom. Removes lots of nutrients from the water. Not native and not hardy.

Rooted Floating Leaf

Water Lilies (Nuphar sp): one of the most desirable pond plants. All hardy ones must have their root stock protected from freezing either in a deep water pond or wrapped in peat moss in the fridge, or placed in a very cool part of the basement/heated garage in a bucket of water. I have one and am hoping it survived the latest over wintering in the fridge. Its best to consult a specialist nursery for advice as to good local choices (Bearberry Creek Water Gardens, Sundre, Alberta 403-638-4231)

Yellow Water Crowfoot (Ranunculus gmelinii): nice little plant with yellow buttercup flowers. Sometimes over winters, native, but only iffy hardy.

Emergent and Marginal

It is very important to note what water depth these plants grow in. Some will tolerate a wide range of water over their crowns; while others will die if planted too deeply. For example, native mint: I killed it regularly when I permanently submerged the crown in as little as 1" of water. The plant tolerates being submerged for a while but needs to spend most of its life in very wet soil or with its crown just above the water

Great Bullrush (Scirpus validus): a wonderful tall plant for water up to 4í deep, dark blue green leaves 2í-7í tall, clumps of brownish flowers in summer, native and hardy.

Common Cattail (Typha latifolia): lives in water 1í to 2í deep. A great plant for phytofilters. Needs a large pond if used as a decorative plant as it grows very tall and very fast. Be careful of the growth tips they are very sharp and strong and can puncture liner ponds. I have mine planted in a open sided container similar to a large milk crate lined with weed cloth. I can drag it out of the pond and divide it when necessary. Native and hardy.

Water Plantain (Alisma plantago-aquatica): another great native plant. Grows in 6" deep water, has large wide decorative leaves. Sends up a tall 1í spike of babies breath like flowers in the summer. Native and hardy.

Blue Flag (Iris versicolour): a water loving iris from eastern Canada. Grows in boggy soil and up to 2" water. Produces beardless Siberian-iris style flowers in late spring. Easy to grow from seed. Many colors to choose from. Native and hardy.

Yellow Water Iris (Iris pseudacorus): taller than blue flag irises. Produces yellow or cream beardless flowers in late spring. Can tolerate slightly deeper water, up to 1í. There is a great stand of this iris in the Japanese section of the Devonian Botanical Gardens in Devon SE of Edmonton. Non-native (of European origin), but hardy

Water Sedge (Carex aquitilis): a nice grass like plant for pond margins. Tolerates 1" water above its crown. To tell the difference between sedges and rushes remember this: sedges have edges, rushes are round; sedges have solid triangular stems and leaves that are flattened and also triangular, rush stems are round and hollow without joints like grasses; the leaves are round too. Native and hardy.

Knotted Rush (Juncus nodosus): thin round stems in a nice green color. The interesting little brown tufts in summer are the flower parts. Grows in 2" water. Native and hardy.

*a note on rushes, sedges, and bog grasses: there are many species native to Alberta, but most are very hard to identify. I have a number of them growing in my ponds but I havenít listed any more than the two above because I canít be sure of their names.

Marsh Marigold (Caltha palustris): a bog plant that produces lots of bright yellow flowers in early spring. Single and double flowering cultivars are available. Keep crown above water level. Native to eastern Canada, hardy.

Arrow-leaved Coltsfoot (Petasites sagitattus): a bog plant with large downy silver leaves, flowers before leaves emerge. Native and hardy.

Palmate-leaved Coltsfoot (Petasites palmatus): same as above but with maple leaf shaped leaves really nice plant. Native and hardy

Wild Mint (Mentha arvensis): bog plant that has nice 6" candelabra spires of tiny lilac flowers. The leaves have wonderful mint scent. Used as a medicinal plant by the Cree. Native and hardy.

Non-Hardy Ornamentals

The next few plants are just for fun in an outdoor pond. None are hardy over winter but some can be cultivated in an aquarium

Bacopa (Bacopa caroliniana): full sun, small blue flowers, grow partly submerged.

Umbrella Palm (Cyperus alterifolius): tall umbrella like leaves, sun to part shade submerge to 6" or leave crown above water, fertilize regularly, snails can damage new growth.

Water canna: I havenít tried this one but the flowers look nice.

Lobelia (Lobelia cardinalis): spikes with red tubular flowers, maroon leaves.

Monkey Flower (Mimulus guttatus): blooms with yellow snapdragon shaped flowers.

Houttuynia cordata variegata: striking red, green and cream leaves, white flowers in summer.

Variegated Pennywort (Hydrocotyle sibthorpioides): cream and green leaves.

Water Clover (Marsilea mutica): clover shaped leaves that will float on the surface

Jungle Val(Vallisneria americana): an aquarium plant that does very well in a pond, but remember to remove it well before winter.

You can also try putting other aquarium plants into a small pond. Or use a patio whisky barrel or other smaller container. You will see that many of our common aquarium plants will flower readily outside in the sun.

Plant Care

In nature water plants grow in a variety of soils, quite often they are clay based. I have found using very heavy soil causes anaerobic decay and often the plant dies. Using garden soil causes large outbreaks of algae especially hair algae. I now use a sand-based mixture formulated for pond plants that I found at a garden supply center. It is easy to mix up your own: use 50% quartz playground sand (3mm to 5mm) or sand blasting sand, 25% well rotted peat moss and 25% unscented pure clay based nonclumping cat litter. Mix up and use as needed. Donít use dry or baled peat moss, but go to a landscape bulk supply center and bag up some heavy wet peat moss. If you have no choice take the dry stuff and pour lots of boiling water over it and leave it for a few days to soak. I pot almost all my plants in plastic-mesh aquatic pots. These pots have open lattice sides and bottoms. I line them with landscape fabric to stop the soil mixture from leaking out. After potting I push an aquatic plant tab fertilizer into the soil beside the plant, then top off the soil with some pea gravel to keep everything in place.

References:

Bearberry Creek Water Garden Catalogue 2001, RR2 Sundre, Alberta Canada T0M 1X0

tel: 403-638-4231

Gadd B, Handbook of the Canadian Rockies, 1986 Corax Press

Johnson D, Kershaw L, MacKinnon A, Pojar J, Plants of the Western Boreal Forest and Aspen Parkland, 1995 Lone Press

Robinson P, Readerís Digest Complete Guide to Water Gardening, 1997 Readerís Digest Assoc

Wright, G, Alberta Water Gardening, 1999 Gary Wright

Water Garden Websites

www.aquascapeontario.com

www.aquaticfeatures.com

www.atponds.com

www.clarkekoi.com

www.dubebotanicalgardens.ns.ca

www.humbernurseries.on.ca

www.hydrospherewatergardens.com

www.pacificpondsplus.com

www.pondsbeautiful.com

www.rainforestnurseries.com

Other Sources for Plants and More Information

Hawaiian Botanicals; 6011 No7 Rd, Richmond, BC, V6W 1E8; 604-270-7712 (water lilies and lotus)

Moore Water Gardens; Box 70, 4683 Sunset Rd, Port Stanley, Ont, N5L 1J4; 519-782-4052

Parkside Gardens; 251 Demetri Way, Saltspring Island, BC, V8K 1X3; 250-653-4917

Reimer Waterscapes; Box 34, Tillsonburg, Ont, N4G 4H3; 519-842-6049

Segger Koi Farm; 5371 Ross Rd, Abbotsford, BC; 604-857-7783

The Lily Pool; 33241 Pollock Rd, Keswick, Ont, L4P 3E9;905-476-7574

Water Arts Inc;††††††††††††††† 4158A Dundas St. W, Etobicoke, Ont M8X 1X3; 416-239-5345?


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