If you drive along the mountain highways of southwestern Colorado in mid to late summer, you’re likely to see small pink or purple colored flowers lining the road and hillsides, especially in areas that have recently experienced wildfire. In all likelihood, you are looking at Fireweed. Fireweed can spread across hillsides and get a bit invasive if not managed on a residential property. In this article, we’ll do a deep dive on growing and caring for Fireweed.
There is more than one flower called Fireweed. The plant referenced in this article should not be confused with Senecio madagascariensis, or South African Fireweed, a noxious and toxic daisy-like weed that is considered invasive. This Fireweed, Chamerion angustifolium, is native to North America.
Growing Fireweed
Fireweed is a fun plant to grow in your garden, but before we get started sowing seeds, let’s run down some important facts about this lovely wildflower.
- Latin name: Chamerion angustifolium
- Other names: Great willowherb, rosebay willowherb
- Native to: Most of the western US and Canada and into the Midwest and Southeast
- Invasiveness: Moderately
- Tenderness: Perennial
- Sun: Full sun
- Water: Regular moisture
- Soil: Rich, well-drained soil
- Hardiness zone: 2-7
- When to plant: Sow seeds in the fall
- Spacing: 36 inches
- Plant height: 1-6 feet
- Bloom period: Brief, mid to late summer
- Container friendly: Yes, encouraged
- Fertilizer: Dry fertilizer containing nitrogen, phosphorus, and potassium
- Toxicity: No
- Drought Resistant: Somewhat
- Deer resistant: Unknown
- Pest resistant: Yes
Fireweed (Chamerion angustifolium), which is known as Great willowherb in Canada and Rosebay willowherb in the UK and Ireland is an herbaceous perennial native to large swaths of North America, Canada, and the United States in particular. Even in its native range, it can be a bit invasive, so care must be taken to contain the plant. It grows in full sun in damp, rich, organic, well-drained soil. It thrives in zones 2-7, so unfortunately more tropical regions won’t successfully grow this plant.
These plants vary in height, growing from 1 to 6 feet with some reports of even 9 foot tall Fireweed. They bloom briefly in mid to late summer and don’t mind a dry fertilizer containing nitrogen, phosphorus, and potassium. They are not known to be toxic, are somewhat drought resistant, may be deer resistant, and in their native range are extremely pest resistant.
Water
Fireweed likes it a little bit wet for a drought-tolerant plant, so regular waterings are a must. They can go a few days without, though, especially once fully established. After a few years, it won’t need quite so much attention from you.
Sunlight
Fireweed grows best in full sunlight conditions. In the wild, it can be found growing on grassy hillsides mostly devoid of trees.
Soil
This wildflower likes rich, well-drained soil that’s amended with lots of organic material like leaves. Piling autumn leaves over your patch of Fireweed is a good way to continue nourishing the soil in which it grows. Be mindful not to plant this flower in compacted soils that don’t drain well. While it likes regular water, it’s not a fan of soggy soil conditions.
Fertilizing
You can most likely get away with not putting any fertilizer on this wildflower, instead opting to add rich compost to the soil each year. If your plant seems to be struggling, consider adding a dry fertilizer containing nitrogen, phosphorus, and potassium.
Invasiveness
Fireweed is known to spread underground through rhizomes, which can make it a nuisance if you don’t want it taking over. While not exactly invasive in its native range, it can be a little bit difficult to control. This plant is a good candidate for container gardening, as the container will reduce the likelihood of unwanted spread.
Growing Fireweed in containers
Fireweed is a good candidate for growing in containers, as it can spread through rhizomes and become a pest, even in its native range. Just be mindful that you’re amending the soil with nutritious, organic material every year and providing occasional fertilizing. This plant can also be a little bit on the thirsty side for a drought-tolerant plant, so be mindful that it gets adequate water when growing in a pot.
Common problems
Fireweed is a hardy plant with very few pests or diseases impacting it. The biggest problem gardeners face is overwatering, nutrient-poor soil, and poorly draining soil.
Propagating Fireweed
In late summer after the flowers have run their course, you can collect and briefly store Fireweed seeds. If you want to propagate more for the following year, sow seeds directly into the soil in fall. Fireweed is also known to spread underground through rhizomes, which can make it a nuisance if you don’t want it taking over.
Wildlife attracted by Fireweed
Fireweed is known to attract bees, flies, butterflies, and hummingbirds alongside a number of other native pollinators. It is an excellent flower to plant if you want to attract more pollinators to your yard and support your native pollinators.