Arrowhead
Sagittaria latifolia
also called broadleaf arrowhead, duck potato, wapato
Bold arrow-shaped leaves and tiers of three-petaled white flowers standing straight out of the shallows: the classic native for the pond edge, and a working crop besides.
- Type
- Flower · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- White
- Sunlight
- Full sun
- Watering
- Aquatic; plant in mud under 5–30 cm of water
- Soil
- Mud; pond margins and standing water to 30 cm deep
- Feeding
- Gentle all-organic
- USDA zones
- 4a–10b
- Frost tolerant
- Yes
- Plant out
- 14 days after the last spring frost
- Plant spacing
- 11.8 in
- In-row spacing
- 9.8 in
- Between rows
- 15.7 in
- Square-foot density
- Not suited to SFG
- Root system
- Rooted in the mud, under water
- Working depth
- 6–18 in
- Can reach
- 24 in down where the soil allows
- Spread
- 18 in–3 ft across, about 1–2× the width of the plant
- Shallowest pot
- 8 in of soil
It roots into the silt and gets its air down from the leaves, so it drowns in nothing and dies in an afternoon out of water. Plant it in a mesh basket of heavy loam, topped with gravel, and set the basket at the depth the leaves want.
The habit is Arrowhead’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- When
- Wapato tubers in mid to late fall, as the leaves yellow and die back.
- What to look for
- Tops collapsing; tubers full-size at the runner ends in the mud, chestnut-brown and buoyant.
- How to harvest
- The traditional way is barefoot: loosen the mud with your feet and the freed tubers float. A garden fork through the pond-edge muck works too, with less poetry. Take the big ones, leave the rest to regrow the stand.
- How often
- Once a fall, from an established colony only.
- Storing the crop
- Keeps a few weeks cool and damp like potatoes, which they cook like: roasted or boiled, chestnut-sweet. Ducks and muskrats run the same harvest without asking.
- Aphids Aphids clustering on the emergent stems in summer
- Muskrats and waterfowl dig the tubers, which in a small pond can mean protecting the crowns with stones
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Aphid midge Aphidoletes aphidimyzaHunts Aphids
A tiny midge whose orange maggots paralyze aphids and drink them dry, twenty or more each. Sold as a greenhouse biological control and resident outdoors wherever there are small nectar flowers and an unsprayed aphid colony to find.
- Assassin bug ReduviidaeHunts Aphids
A patient ambusher with a curved beak it drives into whatever it catches — caterpillars, beetles, bugs, and the occasional bee, so count it a generalist rather than a specialist. It will jab a careless finger too, so admire it and leave it be.
- Big-eyed bug Geocoris spp.Hunts Aphids
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Damsel bug NabidaeHunts Aphids
A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in.
- Dragonflies & damselflies OdonataHunts Aphids
Aerial hunters that take mosquitoes, midges and small flies on the wing all day, and whose larvae spend a year or more clearing the same insects from the water. A pond with planted margins and no fish is the way to have them.
- Garden birds PasseriformesHunts Aphids
Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray.
- Green lacewing Chrysoperla carneaHunts Aphids
Its bristly larvae — "aphid lions" — impale aphids, mealybugs, thrips, and mite colonies, eating hundreds a week. Adults feed on nectar and pollen from small open flowers and overwinter in hollow stems left standing.
- Hoverfly SyrphidaeHunts Aphids
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Aphids
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Minute pirate bug Orius spp.Hunts Aphids
A pinhead-sized true bug that is the best natural check on thrips, and happily spears aphids, mites, and insect eggs too. It needs pollen when prey is scarce, so keep something flowering nearby.
- Parasitic wasps Braconidae & TrichogrammaHunts Aphids
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
- Praying mantis MantidaeHunts Aphids
A sit-and-wait ambusher that snatches caterpillars, beetles, and anything else that wanders close — friend and foe alike, so count it a mixed blessing. Tall, structured plantings give it perches and egg-case anchors.
- Soldier beetle CantharidaeHunts Aphids
Soft-winged beetles seen mating on flower heads in high summer; adults and larvae both take aphids and soft grubs. Open composite flowers are their landing pads and hunting grounds.
- Spiders AraneaeHunts Aphids
Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense.
The autumn tubers are wapato, the "duck potato": a staple food of Indigenous nations across the continent, gathered by loosening them from the mud with the feet until they float. Ducks and muskrats will harvest theirs without being asked.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com