Stinging nettle has a well-earned reputation as a nettlesome plant or, as many say, a weed. But like the much-reviled dandelion, stinging nettle makes for good eating. So much so that many gardeners grow it for food as well as for medicinal uses. To be clear, the stinging part is real. This plant has tiny hairs on the foliage that contain toxins. If your skin brushes against the leaves, you'll get a sting that causes an itchy rash. To make the leaves edible, they are harvested while young, then they are boiled to neutralize the toxins.
Stinging nettle is a member of the genus Urtica, a broadleaf, perennial plant. It can also be categorized as a noxious weed and is quite invasive if not controlled. Nettles are distant relatives of mint, another invasive herb. Do not confuse these plants with dead nettle (Lamium maculatum), a harmless perennial plant used in shade gardens.
Stinging nettles usually grow to about 3 to 4 feet tall. They often grow in masses, forming a monoculture. The leaves have distinctly serrated edges, with each leaf margin looking like a row of pointed teeth. The plant has greenish flowers that are very small and numerous. The flowers grow along stems that shoot out from joints where leaf stalks meet the main stem.
|Botanical Name||Urtica dioica|
|Common Name||Stinging nettle|
|Plant Type||Herbaceous perennial|
|Mature Size||3 to 6 feet tall and 6 to 12 inches wide (per stalk)|
|Sun Exposure||Full sun to part shade|
|Soil Type||Rich, well-drained loam|
|Soil pH||5.5 to 7.5|
|Hardiness Zones||3 to 10|
|Native Area||Western United States|
How to Grow Stinging Nettles
In nature and in public areas, stinging nettles take advantage of disturbed soils, including areas along roadsides. Because they prefer nitrogen-rich, well-aerated soils, however, their favorite habitat is garden borders. In fact, the presence of stinging nettles signifies a fertile, loamy soil.
Given their classification as invasive, it's no surprise that growing stinging nettles is easy. The plants spread via rhizomes (underground stems with roots) and can be aggressive multipliers, so take steps to keep them in check if you don't want them to take over your bed.
Stinging nettle does well in both full sun (up to 6 hours of direct exposure each day) and part sun (a few hours of sunlight).
Nettles grow and taste best when planted in moist, loamy soil. In the wild, they prefer the damp, open soil along streambeds and the nutrient-rich soil of pastureland. But they are tolerant of many soil types and pH levels.
Keep the soil moist during the spring, to ensure a good harvest. After the harvest is over, you may not need to water the plants unless the conditions are unusually dry and the plants seem to be suffering. If there is no rain, watering nettles with about 1 inch per week will support vitality.
Temperature and Humidity
Stinging nettles are not fussy about temperature or humidity levels. They are drought-tolerant and can thrive in a wide range of climates.
You do not need to feed stinging nettles, but because they love rich soil, plant them with compost, and add compost, manure, or other organic amendments annually to provide plenty of nutrients.
Toxicity of Stinging Nettles
The itchy rash you get from stinging nettles is the result of a toxic combination of formic acid (also found in ants), histamine, acetylcholine, and 5-hydroxytryptamine. Pets are also affected by the hairy plant, through contact with the skin or ingestion. If a cat or dog eats nettles, they can experience significant symptoms, including severe irritation (they may drool profusely or paw at their mouths), vomiting, and twitching. There are even reports of dogs dying from extensive exposure.
For these reasons, planting stinging nettles is not recommended wherever children or pets may come in contact with them.
Stinging nettles do not need pruning, per se, but it's a good idea to cut them back after the harvest to prevent the plants from spreading their seeds and invading the rest of the garden. Cut off the flower (and seed) heads when they appear in early summer. Later in the season, as the foliage begins to yellow, trim the plants to about 4 inches tall, using loppers. Leave the cuttings on the soil, if possible (and if there are no seeds); they're good for soil health and will serve as a mulch for winter and the next spring.
If you find nettles sprouting up where they aren't wanted, simply pull them up (wearing heavy gloves), roots and all. You can compost the plants or leave them on the ground if there are no seeds.
Harvesting Stinging Nettles
Stinging nettles have diehard fans the world over. Their young greens taste somewhat like spinach but have a wild, peppery zing. While the greens typically are eaten only when they're young, the leaves of first-year plants don't taste as good as those from older plants. You can harvest only a few leaves at a time, so it takes several plants to feed one person during the harvest season.
Begin harvesting the leaves when the plants are about 10 inches tall and before any flowers appear. Snap off the stems about 3 inches from the top of each plant, wearing gloves to protect your hands. Also, wear pants and a long-sleeve shirt if you have to get into the patch of nettles. When young, both leaves and stems are good for eating, but the stems quickly become fibrous near the end of harvest season. Be sure to boil or steam the foliage before eating it.
In most areas, nettles are good to eat starting in May and extending into June. You'll know the harvest season is over when the taste turns bitter and/or you see flowers on the plants.