Wild Fennel - Natural Dyeing

Wild fennel is a non-native plant and is considered invasive in California, especially along the coast. From July to August, its small, bright yellow flowers light up the roadsides, making it easy to find and harvest. Depending on the average daily temperatures, the harvesting window may be shorter or longer. The stalks, fronds, and flowers produce beautiful yellows. For the most vibrant yellow, use a higher proportion of flowers. It hosts the larvae of the anise swallowtail butterfly, so even though it’s invasive, I always leave some flowers behind. An iron after bath will shift the yellow to chartreuse, moss, and olive.

Folklore & Magick: Used for protection, purification, and enhancing courage, strength, and longevity. It's been used to ward off evil spirits, repel curses, and even prevent unwanted guests from entering homes by placing seeds in keyholes.

Range: particularly in temperate climates. It's a Mediterranean native that has naturalized globally, throughout much of North and South America, South Africa, and parts of Oceania(Australia) and the British Isles. You can find it thriving in grasslands, farmlands, coastal areas, and even gardens.

Growing Habitat: Wild fennel thrives in sunny, disturbed areas, particularly along roadsides and in open, dry habitats such as coastal areas, riverbanks, and fields.

Harvest Time: mid to late summer or until the plant stops flowering

DyeStuff: Flowers, fronds, and stalks. The more flowers, the better.

Fabric Samples are a mix of white and mixed linen, cotton, wool, and silk

Dyeing Instructions can be found in my book ‘The Natural Dye Handbook’. This is an affiliate link for bookshop.org. This means that if you purchase through my link, I may earn a small commission, at no extra cost to you.

More information is available to paid members on my Patreon. If you're interested in subscribing to my Patreon and supporting my exploration of natural dyes. My Patreon is mainly focused on slow stitching, but I’ve begun posting about four natural dye plants each month.

You can find sashiko thread naturally dyed with fennel and other natural dye plants in my shop

I’m teaching at Art Stays this September. If you are interested in exploring your landscape and foraging for plants that produce natural dyes and learning more about how different mordants affect color, this is the  Natural Dye Retreat for you. There are other workshops happening at the same time so please check those out as well.

This is a photo I took near my house on July 29, 2025. It grows by the post office I like to go to. This bunch is over 6 ft tall. It's gigantic. This is the plant I gathered from last year and used to dye the samples in my book. It's also the plant I used back in 2020. Other fennel plants are growing in the ditch and parking lot, too. This is already on my plant map. It feels like an old friend, and I love visiting it. It gets bigger every year.