Pontederia

( pon - teh - DEER - ee - uh )

At-A-Glance Information

Commonly known as Pickerel Weed, this genus of aquatic perennials includes plants that need full sun to light shade to perform well. Species are native to the Americas, and typically reach 2-4 feet tall and 2-2.5 feet wide when mature. Flowers bloom from late spring through fall. Flowers are blue-purple typically, but can also come in pink or white depending on the species and varietal. This plant is great at adding interest to pools of water, and will go dormant in wintertime. Grow Pontederia flowers as members of marsh, stream, or pond ecosystems, or simply grow them in container water gardens on patios or balconies.

Pontederia species and varietals

The genus Pontederia is the type member of the plant family Pontederiaceae and includes 27 distinct species. Pickerel Weed grows best in zones 1-24, H1 and H2 (To find your zone, click here: Zone Map).

Pontederia azurea (Anchored Water Hyacinth, Water Orchid, Floating Water Hyacinth)
These plants are free floating aquatic perennials produce waxy green leaves with a rounded shape, and a long flowering stem that rises above the water's surface. Flowers are lavender-blue with yellow blotches at their centers. These plants are considered invasive in some areas of the world, especially when they escape cultivation.

Pontederia cordata (Pickerelweed, Pickerel Weed)
These emergent plants grow in flooded conditions, and is often found in areas where water level fluctuates naturally. Flowers bloom in late summertime, and are purple with yellow markings. Fruits follow blooms. These plants are popularly used in garden ponds and other water features. Individual plants reach up to between 2 and 4 feet tall when mature and in bloom.

'Alba'

'Pink Pons'

'Sunsplash'

Pontederia crassipes (Eichhornia crassipes) (Common Water Hyacinth)
These free-floating perennial aquatic plants are native to tropical and subtropical South America, and produce broad, thick green leaves. Flowering stems can rise above the water's surface up to 3 feet. Flowers are lavender to pink in color. These are some of the fastest growing plants in the world, able to reproduce by runners or stolons; mats can double in size in just one to two weeks' time.

Pontederia sagittata
These perennials form basal leaves that are sometimes reddish, and inflorescences that hold more than 50 flowers each. Blooms are blue, lilac or white, and bloom in terminal spikes. These plants are native to Mexico through Central America, down to eastern and southern Brazil. It is typically found growing along the edges of rivers, lagoons, ponds, and swamps in its native range.

Pontederia vaginalis (Heartshape False Pickerelweed, Oval-Leafed Pondweed)
These plants are native to Asia and the Pacific Islands, and is known as an introduced (and usually invasive) species in many areas around the world, including the United States. The species can produce annual or perennial plants with shiny green leaves and purple-blue flowers that open while the inflorescence is still under the water's surface.

Caring for Pontederia

Pontederia, or Pickerel Weed, is best when grown in a foot of freshwater with its roots in soggy soil. These plants can be grown in ponds or simple container water gardens on a patio or balcony. They are typically either grown from seed or purchased as bare root, dormant rhizomes. These aquatic plants appreciate a growing environment in a freshwater pond or other water feature in full sun. They also grow well along the edges of streams, ponds, and marshes. Rhizomes are best set out in springtime, about 4 feet apart for best coverage. Plant them a few inches deep, with their growing points facing upwards towards the sky. The rhizome should fit snugly in the muddy soil substrate; small rocks can be used to weigh down the area around the planting if necessary. These plants are not picky about substrate, as long as it is muddy (not too rocky), and can grow well in a wide range of pH levels. Pickerelweed does not require fertilizing, pruning, or mulching. Every few years, plants may need to be divided, depending on the size of the space they are being grown in. A good rule of thumb to decide when to divide is to notice if flowering or foliage has been struggling lately, or if plants are simply not performing well. For instructions on how to successfully divide Pontederia plants, see the Propagation section below.

Growing Pontederia in Containers
Plant your Pickerelweed rhizome in a fabric plant pot in muddy substrate. The fabric pot will allow moisture and oxygen to flow freely to the root system, and will also ensure that your Pickerelweed is easily accessible if it needs to be removed at any time for maintenance. Place your container in a spot that gets full sun; ideally, Pontederia plants appreciate between 6 and 8 hours of direct sun each day. Replenish water levels to keep up with evaporation, always keeping the water level below the bottom leaves of the plants. Because Pontederia plants will form clumps over time, in small-space containers they will need to be divided every few years. For instructions on how to successfully divide Pickerelweed plants, see the Propagation section below.

Harvesting Pontederia
Take care when harvesting and consuming these plants, as heavy metals or other sediments in the water where Pickerel Weed grows can leach into plant material. Make sure to have water tested for heavy metals before consuming any part of these plants. In addition to being a gorgeous aquatic ornamental plant, Pontederia also has some edible qualities, and can be considered an 'edimental' garden flower. Young, unfurled leaves and leafstalks as well as the seeds are harvested and consumed. Young leafstalks can be eaten raw (with any attached, unripe fruits stripped off) or boiled. Seeds are edible raw, though they can also be roasted, parched, or boiled. They make a great flour, as well.

Propagation

Pontederia, or Pickerel Weed, typically will self-seed and spread via rhizomes on its own, but these plants can also be intentionally propagated via seed or division. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it may not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Pontederia, follow the instructions below:

Propagating Pontederia by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Physostegia seeds will need a period of cold-stratification in order to germinate. To complete this process, first place seeds in a bag or other sealable container filled with moistened sand or peat moss. Then, place the container in the refrigerator (or similarly cool, dark space) for 2-3 months. The ideal temperature for cold-stratification is around 40 degrees Fahrenheit. After this period has passed, remove seeds from the container.
Get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Pontederia by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a trowel, lift up your existing plant. Start from the outside and work your way in to avoid damaging the rhizome(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Separate your plant into multiple segments, ensuring that each one has at least one thick root section attached with a healthy amount of rhizomes and leaves.
Prepare your pot(s) or new planting site(s) with muddy substrate. Then, plant your divisions.