Grow curled pondweed fully under water, in cool sun. Curled pondweed is Potamogeton, also sold as curly-leaf pondweed. Check local rules before you buy, because many states restrict it.
Keep it fully under water, in cool sun
| Factor | Recommended | Avoid |
|---|---|---|
| Light | Full sun or part sun, with enough light to reach the leaves under water | Do not grow it in a dry bed in deep shade |
| Water | Fully submerged in still or slow cool freshwater | Do not let the stems dry in air |
| Site | A lined pond or water garden where your state allows it | Do not stock it where sale or possession is prohibited |
| Season | Expect strong growth in cool water, then a midsummer dieback after winter buds form | Do not treat that summer collapse as a failed planting and dump the stems |
curled pondweed has to stay under water. Full sun or part sun in a legal pond is the usual home, and cool water keeps the wavy leaves firm. [1] It is a rooted oxygenator with alternate leaves that look ruffled, like a lasagna noodle, and feel finely toothed. It has no true floating pads. A short flower spike may sit about an inch above the water in late spring. [2] Stems that dry on a bench do not recover. The plant grows under ice and peaks in spring, then the tops die back in warm midsummer after it sets hard winter buds, called turions, that look like small pinecones. Those buds sprout again when the water cools. It is not a dry-bed plant.
How to grow curled pondweed?
Keep it fully under water in cool sun, in a pond where your state allows it. Expect a midsummer dieback after turions form. Do not let the stems dry.
Does it come back after ice?
Yes, if it is legal in your pond. It grows under ice and in cold water. The tops often collapse in warm midsummer after turions form, then new stems sprout when the water cools.
Plant a weighted bunch or a basket so the leaves stay under water
Shop bunches arrive weighted so they sink. Keep them wet from the bag to the pond. Push the weighted ends into silt or fine gravel on the pond floor, or set them in an aquatic basket filled with aquatic soil, then lower the basket so every leaf stays under water. [3] In a small lined pond, about 8 to 40 inches of water over the basket is enough light for the leaves. Lake depths of many feet are not the home-pond start.
- Check local rules before you buy or move the plant. Some states prohibit possession.
- Open the bag at the pond and keep the stems wet. Discard mushy pieces in the trash, not in a ditch.
- Push the weighted bunch into silt or fine gravel, or fill a mesh aquatic basket with aquatic soil, tuck the bunch, and cover the soil with a little gravel so it stays put.
- Lower the basket or bunch so the leaves stay fully submerged in still or slow water.
- Bag extras. Do not toss stems, turions, or mud into a lake, ditch, or storm drain.
How do I plant curled pondweed?
Keep the bunch wet, then push it into silt or an aquatic basket so every leaf stays under water. Bag extras instead of tossing them into a lake.
Does it need potting mix in a flower pot?
No. A draining flower pot of mix dries and kills the stems. Use a pond basket under water, or a tub that never empties.
Cut a stem and tuck it again — bag extras
New plants start from stem pieces and from turions, not from a seed packet. Cut a healthy stem a few inches long and tuck it the same way as the first bunch. Clip extras before the clump mats the surface, and bag every piece you do not replant.
- Cut a healthy stem a few inches long.
- Tuck it into silt or the same aquatic basket, leaves under water.
- Clip extras as the clump reaches the surface. Leave pulled stems at the pond edge only if you will bag them the same day after small animals crawl back.
- Bag what you do not keep. Fragments and turions start new plants in the next pond they reach.
How do I get more plants?
Cut a healthy stem and tuck it under water. Seed plays almost no part. Bag pieces you do not keep.
Not Canadian pondweed — and not Cape pondweed or water caltrop
Canadian pondweed is Elodea, with three leaves in a whorl and a smooth feel in the hand — see How to Grow Canadian Waterweed. Curled pondweed has one leaf at a node, wavy edges, and fine teeth you can see. [4] Cape pondweed is water hawthorn, Aponogeton, with oblong floating leaves and a scented forked spike — see How to Grow Water Hawthorn. A tag that says Water Calthrops on this shop card is still curled pondweed. True water caltrop is Trapa, a floating rosette of triangular toothed leaves with spiny nuts.
Clasping-leaf pondweed has smooth margins and leaf bases that wrap the stem; the tips are pointed, not blunt. Hornwort has stiff, forked leaves and often floats with no true roots — see How to Grow Hornwort. Fanwort stays under water with opposite fan-shaped leaves — see How to Grow Fanwort. A water lily has round pads with a slit — see How to Grow Water Lily.
Is this Canadian pondweed?
No. Canadian pondweed is Elodea, with three leaves in a whorl. Curled pondweed has alternate wavy leaves with fine teeth.
Is Water Calthrops a different plant?
On this shop card, Water Calthrops is another name for curled pondweed. True water caltrop is Trapa, a floating rosette with spiny nuts.
Keep curled pondweed fully under water in cool sun, set a bunch or a basket so the leaves stay submerged, and bag extras instead of tossing them into a lake.
FAQ
Can I grow it in an aquarium?
Only in cool, unheated water, and only where your state allows it. Tuck the stems so they stay under water, clip extras, and bag every trimming. A heated tropical tank is usually curly Aponogeton, a different plant with a tuber.
Can I grow it in a dry pot?
No. Mix that dries in a day kills the stems. A lined pond, a water garden, or a tub that holds water works only when the plant stays under water.
Can I grow it from seed?
Seed is scarce and slow. The shop start is a wet bunch. Tuck a stem or a turion under water instead.
Are other pondweeds on this card?
No. This card is curled pondweed. Floating-leaved pondweeds, clasping-leaf pondweed, and sago pondweed are other species. Read the Latin name on the tag.
Is it legal to plant in my pond?
Many states list it as invasive and prohibit sale or possession. Check your state agency before you buy. Never toss extras into a lake, a ditch, or a storm drain.
Can I mix it with other oxygenators?
In a legal pond you can, but this plant spreads from fragments. Give each kind space, and bag extras so one clump does not fill the water.
Recommended plants
References
- [1] UF/IFAS Center for Aquatic and Invasive Plants -
https://plant-directory.ifas.ufl.edu/plant-directory/potamogeton-crispus/ - [2] Pennsylvania Sea Grant -
https://seagrant.psu.edu/resources/resource-item/curly-leaf-pondweed-ais-fact-sheet/ - [3] Plants for Ponds -
https://plantsforponds.co.uk/products/curly-pondweed-potamogeton-crispus-1 - [4] Montana State University Extension -
https://www.montana.edu/extension/invasiveplants/documents/publications/extension_publications/Curlyleaf_pondweed.pdf
More first-season notes by plant are gathered in How to Grow Guides.
Updated: Reviewed by Bosquelle Editors