Chamaenerion

( kam - ay - NER - ee - on )

At-A-Glance Information

This genus of flowering plants have species commonly referred to as Willowherbs or Fireweeds. These upright herbaceous perennial flowers have profuse shows of purple to pink blooms in spring and summertime. Each short-lived flower is followed by a narrow seed pod, which explodes to release its contents along with a web of silky white hairs. Plants will form clumps over time, and in some areas are considered to be a bit invasive. Take care when planting these flowers in the landscape, as ingestion of plant parts is known to be very toxic to cattle.

Chamaenerion species and varietals

The genus Chamaenerion includes six species and is a member of the plant family Onagraceae. Its common name, Fireweed, refers to its tendency to be a pioneer plant in areas that have experienced wildfires. Fireweed grows well in USDA hardiness zones 2-7 or Sunset growing zones A1-A3, 1-7 and 14-21 (to find your zone, click here: Zone Map).

Chamaenerion angustifolium (Epilobium angustifolium, Epilobium spicatum) (Great Willow Herb, Narrow-Leaved Fireweed, Rosebay Willowherb, French-Willow)
This perennial flowering plant requires full sun and moderate water. The flowers attract beneficial insects and hummingbirds. Considered wildflowers, they can quickly form colonies in open swaths of land, but are also beautiful in wild gardens. They reach 2-5 feet tall and 1.5-3 feet wide, and hold loose clusters of pink, rose purple, or white flowers in early summer. Fireweed is native to North America and Eurasia, and is Alaska's most popularly known wildflower. Cultivar 'Album' has white flowers.

Chamaenerion latifolium (Epilobium latifolium) (Dwarf Fireweed, River Beauty Willowherb, River Beauty, Niviarsiaq)
This arctic species is native to northern regions of the Northern Hemisphere, and produces a clump-forming plant with a woody base. Dwarf Fireweed, as its common name suggests, is a bit smaller than other species, topping out around 12 inches tall. Plant parts are consumed by the Inuit; leaves and shoots are edible, as are flowers and fruits. Blooms are pink, sometimes white, and flower in late spring to early summer. This flower is the national flower of Greenland.

Chamaenerion fleischeri (Epilobium fleischeri) (Alpine Willowherb, Dwarf Fireweed, Fleischer's Willowherb)
Reaching between 4 and 16 inches tall at maturity, this erect species of Willowherb is native to the Alps in France, Germany, Italy, Switzerland, and Austria. Flowers are fragrant and pink, blooming in late June through August in their native range.

Caring for CHAMAENERION

Take care when planting these flowers in the landscape, as ingestion of plant parts is known to be very toxic to cattle. These strong spreaders are best planted in a spot in the garden where their somewhat invasive nature will not disturb the growth pattern of other plants. They grow from rhizome roots, and can be either grown from seed, divided and planted, or be purchased at nurseries where available. Plant these flowers in full sun to partial shade. Ideally, they should be receiving somewhere between 6 and 8 hours of sun each day for the best blooms. In warmer climates, make sure to provide plants with some shelter from sun during the hottest hours of the afternoon. They appreciate well-draining, rich soils with a pH of between 5.0 and 7.5 (circumneutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. After planting Fireweed, mulch around the base of the plant with organic mulching material to help retain soil moisture and suppress weed growth. Keep mulch away from the plant stems, as this can encourage an environment for root rot issues to take hold.

Water new plants regularly as they establish a strong root system. At maturity, these plants are relatively drought-tolerant, able to pull moisture and nutrients from their rhizome roots to carry them through dry seasons. For the best blooms, however, make sure these plants are getting irrigated at least once a week, or simply irrigate when the top inch or two of soil feels dry to the touch. Fertilize the planting area yearly with an application of about two inches of compost. Pull back mulch, apply compost, work the compost into the soil, and then water it in. Replace mulch afterwards and add more if necessary. This feeding is enough to carry these plants through their growing and flowering seasons, and they will not need any additional fertilizers. Deadhead plants when flower spikes are spent to neaten the appearance of plants. If collecting seed for sowing in upcoming years, make sure to earmark some plants that will not be deadheaded so they can be harvested for seed. These plants grow from rhizome roots, and will need to be divided every few years, especially if they are being cultivated in a cramped space like a tight garden bed or container. For information on how to divide Fireweed, see the Propagation section below.

Propagation

Chamaenerion, or Fireweed, can be propagated either by using cuttings, division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division or cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that the resulting plant may not necessarily be the same as the parent plant the seeds are harvested from. To propagate your Fireweed flowers, follow the instructions below:

Propagating Chamaenerion by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new flower.

Propagating Chamaenerion 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. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed pods ripen in late spring to summer, and can be simply cut off of the plant and placed into a paper bag for temporary storage. Store the seeds over the winter in cool (but not frosty), dark conditions.
In early spring of the next year, 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 is usually pretty quick for these plants, occurring within 10-14 days after sowing.
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 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until seedlings reach a few inches tall. Young seedlings are best stored in a shaded area of a greenhouse; direct sun can scorch the developing leaves.

Propagating Cerastium by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost, and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, 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:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section to grow from.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water them in thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout.

Fireweed seed pods take the place of flowers after they have faded. They are long, thin, brown-red, and contain feathery white material attached to seeds.

Chamaenerion seeds are very small, and typically range in color from brown to tan.

Problems and Pests

Fireweed can be a pest in itself; these plants freely reseed, their small seeds carried over relatively far distances through the wind using feathery attachments. These plants can also form colonies by spreading underground rhizome roots, and can out-compete native plants in some areas. It typically colonizes areas with disturbed soils, like roadsides, empty fields, and pastures. It is very toxic to cattle, horses, and other livestock, so take care when planting if you are in an area with high rates of animal husbandry. Though typically resilient plants, Fireweeds are susceptible to developing issues with the following pests and diseases: