Ornamental · Pontederiaceae
Pickerelweed
Pontederia cordata
An easygoing native pond marginal that throws up blue flower spikes all summer, and all it asks for is full sun and wet feet.
Full sun
USDA 3–10
2–4 ft · 0.6–1.2 m
Overview
Pickerelweed is a native aquatic that turns up along the edges of ponds, ditches, and slow streams across a lot of North America. It roots down in the mud right at the water's edge and holds its leaves and flower spikes up above the surface, which is really all gardeners mean when they say emergent marginal. You'll see glossy, heart-shaped leaves at the base, and from early summer into fall it sends up soft spikes of violet-blue flowers.
It pulls its weight for wildlife, too. The flowers bring in bees and other pollinators, and ducks and waterfowl go for the seeds and foliage. It's a hardy perennial, so it takes winters in stride from zone 3 all the way to zone 10, dying back in fall and popping up again from the rhizome each spring.
There are really just two things to keep in mind. The roots have to stay constantly wet to shallowly submerged, because this is a wetland plant and it can't dry out, and that same get-up-and-go that fills a pond edge with bloom will wander if you let it. Want to keep things tidy? Grow it in a basket where space is tight and it stays a generous, well-behaved clump.
Care
The short version: give it full sun and keep its feet wet, rooted in rich mud or loam with the crown under just a few inches of water, and tuck the rhizomes into a basket so they don't take over.
Light
Pickerelweed flowers best in full sun, and that's where you'll get the most spikes and the strongest growth. It'll manage in partial shade too, but you'll get fewer flowers and a looser, leggier plant out of the deal.
Water
This is a real wetland plant, so the roots have to stay constantly wet to shallowly submerged and never dry out. Grow it in mud or rich loam with about 2 to 12 inches (5 to 30 cm) of water over the crown, or in boggy soil right at the water's edge. Just don't plant it any deeper than roughly 12 inches (30 cm), because all that extra water over the crown can kill it.
Soil
Root it in rich organic loam or mud that stays constantly wet to submerged. It's not fussy about pH, and it'll settle in anywhere from 6.0 to 8.0, so most pond mud does the job without any hassle.
Temperature
Pickerelweed's seriously tough, handling everything from -40°F (-40°C) in winter dormancy up to about 100°F (38°C) in summer. That covers zones 3 through 10, so it just overwinters right where it is across most of the country.
Humidity
Since it's growing in or beside water, it never runs short on moisture in the air, so humidity is one less thing to fuss over. The high humidity at a pond edge is exactly where it's happiest.
Feeding
It doesn't need much feeding and mostly looks after itself. If you want to nudge it along, work an aquatic plant tablet into the soil during the spring-through-summer season, but keep it light, because this plant does just fine on its own.
Pruning
Upkeep's about as easy as it gets. Snap off the spent flower spikes through the season, then cut back and clear out the old, dead foliage in late fall or early spring before the new growth kicks in.
Repotting
Every 2 to 3 years, lift the plant to divide and freshen up a crowded clump. How do you know it's time? Rhizomes bulging the basket, smaller leaves with fewer flowers, and the plant heaving itself up out of its pot.
Size & spacing
Plants get to 2 to 4 feet (61 to 122 cm) tall and spread 18 to 24 inches (46 to 61 cm) across. Give each clump some room to widen out, and keep in mind the rhizomes will keep reaching past that spread unless a basket's holding them back.
When to plant
Pickerelweed's all about the warm season. Set divisions or potted plants out in spring once the frost's gone, into mud at the pond margin or a submerged basket, and it'll pay you back with blue spikes from early summer right through fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring; seed germinates best under water and may need cold stratification
- Plant: Spring, after frost, into mud at pond margins or in submerged baskets
- Harvest: Early summer into fall (about June to October)
Hardiness
USDA hardiness zones: 3–10
Temperature: down to -40°C
Troubleshooting
Here's the reassuring part: pickerelweed has no serious pests or diseases, so almost all of its trouble boils down to two things, that it spreads and that it can't ever dry out. Match up what you're seeing below and you can sort it out before it gets away from you or starts to fade.
Wilting and browning from drying out or wrong planting depth
Here's the deal: this is a wetland plant, so it really can't handle drying out, not even once. If the soil goes dry or only damp, or the crown ends up under more than a foot of water, it'll brown and just sit there. So keep the soil constantly wet to shallowly submerged, and fix the depth so only 2 to 12 inches (5 to 30 cm) of water sits over the crown.
Fix:
- Keep the soil constantly wet to shallowly submerged at all times
- Reset the planting depth so only about 2-12 in (5-30 cm) of water covers the crown
- Move container plants to a shallower shelf or raise them on bricks
Spreading rhizomes that crowd a small pond or container
Wondering why it's suddenly everywhere? That's the thick rhizomes at work, and in open mud they build dense colonies that creep into open water and over whatever's next door. The trick is to plant it in a submerged aquatic basket from the start, so the roots stay put. After that, just lift and divide the clump every 2 to 3 years, and snip back any wandering shoots before they get too far.
Fix:
- Grow in a submerged aquatic basket or container rather than open mud to confine the rhizomes
- Lift and divide clumps every 2-3 years, discarding excess rhizome
- Pull or cut back outlying shoots to keep the colony in bounds
Minor leaf feeding from aphids, mites, or caterpillars
Good news on the bug front: pickerelweed has no serious pests or diseases, so anything you find is usually pretty minor. You might spot little clusters of aphids, the fine webbing and stippling of spider mites, or leaf edges that caterpillars have chewed. A strong jet of water knocks the small ones off, caterpillars come off by hand, and honestly the plant just grows past whatever's left.
Fix:
- Hose pests off with a strong jet of water
- Hand-pick caterpillars
- Tolerate minor damage, since this plant has no serious insect or disease problems and usually outgrows it
Toxicity
If you've got pets or kids, here's the good news: pickerelweed is non-toxic to people and animals, and parts of it are actually edible. The young leaves and ripe seeds have been eaten for ages, and the plant's a favorite food for ducks and other wildlife. It does grow in standing water, though, so the one real thing to watch is the usual supervision around a pond.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are totally fine around it. A curious nibble won't poison them, though the pond water itself is a good enough reason to keep half an eye out.
Dogs None
No need to stress if a dog snags a mouthful of leaves. There's nothing toxic in the plant, so it's in no danger from the pickerelweed itself.
Horses Safe
Horses can nibble the leaves at the pond edge and be perfectly fine, since none of it is poisonous to them.
Rabbits Safe
The soft leaves are no trouble for rabbits and don't carry any toxins, so it's a worry-free marginal to have near a hutch or pond.
Livestock Safe
Cattle, goats, and sheep can browse it just fine. It's non-toxic, and it actually feeds a whole bunch of grazing and wild animals.
Birds Safe
Far from being a problem, the seeds and foliage are a favorite for ducks and other waterfowl, and they're no risk to backyard or wild birds either.
People Safe
People are safe too, and the young leaves and seeds are actually edible. Cook the young leaves like a green, and eat the ripe seeds raw or roasted.
No special handling precautions; the plant is safe and even edible. It lives in standing water, so normal supervision around ponds applies.
Varieties
Most of the pickerelweed you'll come across is the plain blue-flowered species, but there are a couple of selections worth knowing about.
'Alba'
Want white instead of the usual blue? This one sends up tall spikes of white blooms from summer into fall.
var. lancifolia
This form has slimmer, lance-shaped leaves rather than the heart-shaped ones you'd see on the typical plant.
Companions
Pickerelweed plays well with other native marginals and pond plants that share its taste for full sun and wet ground, layering the pond edge with different heights and leaf shapes.
Plant near
Water lily (Nymphaea): A classic pond pairing: pickerelweed's vertical blue spikes at the margin complement floating-leaved water lilies in deeper water.
Arrowhead (Sagittaria latifolia): Another native marginal sharing the same shallow-water, full-sun habitat for a layered pond-edge planting.
How to propagate
There are two ways to make more pickerelweed, and one of them is way faster than the other.
DivisionEasy
Spring · One growing season
Division is the quickest and most dependable way to get more pickerelweed, so it's the one to reach for first. Come spring, dig up an established clump and split the thick rhizomes apart, and just make sure each piece keeps some roots and a shoot. Those new bits settle in and fill out over a single growing season.
SeedModerate
Late winter to spring · One to two growing seasons
Seed takes a bit more patience, and it works best when you sow it from late winter into spring. It germinates best under water, even after dry storage, and a stretch of cold stratification gives it a hand. Just give seed-grown plants one to two growing seasons to bulk up to a good size.
Myths
Pickerelweed is the same plant as water hyacinth and just as invasive.
Nope, they're two different plants. Native pickerelweed roots itself in pond mud and pretty much stays put, while water hyacinth floats free and is famous for clogging up waterways. Sure, they're both in the family Pontederiaceae, but pickerelweed is a well-behaved native, not the invasive floater.