Ornamental · Pontederiaceae
Pickerelweed
Pontederia cordata
A native pond marginal that lifts soft blue flower spikes all summer above glossy heart-shaped leaves, on full sun and wet feet.
Full sun
USDA 3–10
2–4 ft · 0.6–1.2 m
Overview
Pickerelweed rises straight out of the shallows along ponds, ditches, and slow streams across much of North America. Its roots grip the mud at the water's edge while its leaves and flower spikes stand clear above the surface, the upright form of an emergent marginal. At the base sit glossy, heart-shaped leaves on long stalks, and from early summer into fall the plant pushes up soft, densely packed spikes of small violet-blue flowers.
Those leaf blades and flower spikes double as food for wildlife. The blue spikes draw bees and other pollinators to their tiny flowers, and ducks and waterfowl strip the ripe seeds and foliage. A hardy perennial, it holds through winters from zone 3 to zone 10, the top growth dying back in fall while the thick rhizome waits below to send up new blades each spring.
Two things shape the plant you see. The roots must stay constantly wet to shallowly submerged, since this wetland grower cannot dry out without the leaves browning, and the same rhizomes that fatten a full clump will creep outward if left loose. Grow it in a basket where space is tight and it stays a dense, generous stand of upright green blades and blue spikes.
Care
The short version: pickerelweed wants full sun and permanently wet feet, its crown rooted in rich mud or loam under just a few inches of water, with the thick rhizomes penned in a basket so the clump stays dense rather than sprawling.
Light
In full sun pickerelweed sends up the most flower spikes and the sturdiest, most upright blades. Set in partial shade it still grows, but the spikes thin out and the leaf stalks stretch looser and leggier toward the light.
Water
This is a true wetland plant, its roots wanting to stay constantly wet to shallowly submerged and never dry. Root the crown in mud or rich loam under about 2 to 12 inches (5 to 30 cm) of water, or in boggy soil right at the water's edge. Sunk deeper than roughly 12 inches (30 cm), the water standing over the crown can kill it.
Soil
The roots take hold in rich organic loam or mud that stays constantly wet to submerged. Pickerelweed is easygoing about pH, at home anywhere from 6.0 to 8.0, so most dark pond mud gives it the footing it wants.
Temperature
Pickerelweed is remarkably hardy, its rhizome enduring -40°F (-40°C) in winter dormancy and its leaves standing through about 100°F (38°C) in summer heat. That reach covers zones 3 through 10, so the clump overwinters in place across most of the country.
Humidity
Rooted in or beside water, it is never short of moisture in the air, so humidity is one less thing to manage. The damp, high humidity at a pond edge is exactly where its foliage stays firm and glossy.
Feeding
The plant needs little feeding and largely fends for itself. To thicken the leaf growth, press an aquatic plant tablet into the soil during the spring-through-summer season, but keep it light, since pickerelweed does fine on its own.
Pruning
Upkeep is light. Snip off the spent flower spikes as they fade through the season, then cut back and clear the old, browned foliage in late fall or early spring before the new blades push up.
Repotting
Every 2 to 3 years, lift the plant to divide and refresh a crowded clump. The signs are rhizomes bulging the basket, smaller, tighter leaves with fewer flowers, and the crown heaving up out of its pot.
Size & spacing
The upright blades and spikes reach 2 to 4 feet (61 to 122 cm) tall, and each clump spreads 18 to 24 inches (46 to 61 cm) across. Give it room to widen, and remember the thick rhizomes keep creeping past that spread unless a basket holds them in.
When to plant
Pickerelweed keeps to the warm season. Set divisions or potted plants out in spring once frost has passed, rooting them into pond-margin mud or a submerged basket, and the upright blue spikes follow from early summer into 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
Pickerelweed carries no serious pests or diseases, so what shows in the leaves and stems traces back to just two things: the rhizomes spread, and the plant must never dry out. Match what you see below and you can act before the clump overruns its space or the blades brown off.
Wilting and browning from drying out or wrong planting depth
The glossy green blades go limp and turn a dull brown the moment this wetland plant suffers drying out, and once the color goes it does not come back. Dry or merely damp soil does it, and so does a crown drowned under more than a foot of water. Hold the soil constantly wet to shallowly submerged so the leaves stay firm and green, and set the depth so only 2 to 12 inches (5 to 30 cm) of water covers 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
Below the mud, pickerelweed travels on thick, fleshy rhizomes that snake outward and knit dense colonies, sending up ever more leaf blades and spikes until they crowd into open water and over their neighbors. Seat the plant in a submerged aquatic basket at planting so those creeping rhizomes stay penned. Lift and divide the clump every 2 to 3 years, and cut back the outlying shoots before they push past the basket rim.
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
Pickerelweed carries no serious pests or diseases, so its broad green leaves stay mostly unmarked. Now and then aphids dot the blades in tight clusters, spider mites veil them in fine webbing and freckle the surface with pale stippling, or caterpillars leave ragged bites along the leaf margins. A strong jet of water strips the small feeders off, caterpillars lift away by hand, and fresh leaf growth soon covers over the rest.
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
Pickerelweed is non-toxic to people and animals, right down to the leaves and seeds. The tender young leaf blades and the ripe seeds have long been eaten, and the same foliage and seed feed ducks and other wildlife. Because it grows in standing water, the one real caution is the usual supervision around a pond.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A cat that mouths one of the glossy green blades takes no harm, since the plant holds nothing toxic. Only the pond water itself calls for the usual watchful eye.
Dogs None
The leaves and stems carry no toxic compounds, so a dog that tears off a mouthful of the green foliage is in no danger from the plant itself.
Horses Safe
Horses can crop the broad green leaves along a pond edge without harm, since nothing in the plant is poisonous to them.
Rabbits Safe
The soft young leaf blades hold no toxins and are safe for rabbits, making this an untroubled marginal near a hutch or pond.
Livestock Safe
Cattle, goats, and sheep can browse the leafy growth without harm. The plant is non-toxic and feeds a range of grazing and wild animals.
Birds Safe
The ripe seeds and green foliage are prized fare for ducks and other waterfowl rather than any hazard, with no risk to backyard or wild birds.
People Safe
The plant is safe for people, and the young leaves and ripe seeds are edible. The young leaf blades cook down like a green, and the ripe seeds are eaten 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
The straight species carries blue flower spikes, but a couple of selections differ in flower color or leaf shape and are worth knowing.
'Alba'
This selection trades the usual blue for pure white, lifting tall spikes crowded with white blooms from summer into fall.
var. lancifolia
This form carries slender, lance-shaped blades that taper to a point, unlike the broad heart-shaped leaves of 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
Pickerelweed can be increased two ways, one filling out a clump of leaves far sooner than the other.
DivisionEasy
Spring · One growing season
Division is the easiest and most reliable way to increase pickerelweed. In spring, lift an established clump and cut the thick, fleshy rhizomes apart, leaving roots and a firm shoot on each piece. The new divisions root down and send up fresh blades over a single growing season.
SeedModerate
Late winter to spring · One to two growing seasons
Seed asks for more patience and sprouts best when sown from late winter into spring. Germination runs strongest under water, even after dry storage, and a spell of cold stratification helps the seed break open. Seed-grown plants need one to two growing seasons to build a full clump of leaves.
Myths
Pickerelweed is the same plant as water hyacinth and just as invasive.
They are two different plants that even look distinct. Pickerelweed is a rooted emergent, anchored in pond mud by its rhizomes and standing its leaves upright, while water hyacinth floats free on the surface and is notorious for choking waterways. Both belong to the family Pontederiaceae, but pickerelweed is a well-behaved native, not the invasive floater.