Purple Dead-Nettle

Native

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  By Jesse Taylor – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20255993

  Self-Heal (Prunella vulgaris var. lanceolate): The leaves of Self-Heal may be obscurely toothed or entirely round, but are not crenate and the leaves are not purple. The many flowers of Self-Heal occur in a single inflorescence above the upper leaves
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Non-Native:

• Common Dead-Nettle (Lamium amplexicaule) has stemless leaves.

Purple Dead-Nettle is native to Europe and Asia. It was introduced to North America through the horticultural trade. It now grows in southern British Columbia and eastern Canada.

Purple Dead-Nettle grows well in disturbed areas. It grows in areas with full sunlight or light shade and moist, fertile soil. It can be found in gardens, orchards, fields, ditches, and weedy edges of woodlands.

Spreads through both seeds and vegetative methods. Flowers can self-pollinate before opening but can also be cross-pollinated by bees and wasps. Roots can form new genetically-identical plants by creeping (via horizontal roots growing outwards from the main plant and sending up clones) or by forming new plants from root fragments. Purple Dead-Nettle can germinate year-round when buried at depths of 0.5 – 2 cm. One plant can produce 300 seeds and can be viable for up to 9 years.

Purple Dead-Nettle is sometimes sold for ornamental purposes, so the nursery trade and gardeners are considered the plant’s main vector of spread. Purple Dead-Nettle is also spread in contaminated soil and by dumping garden waste.

Purple Dead-Nettle is found in the Lower Mainland (BC) and at a small number of locations in the Sea to Sky Region, so PREVENTION of further spread is key.

 

Learn to identify Purple Dead-Nettle: use the images presented in this profile page to learn how to identify Purple Dead-Nettle.

What to do if you spot it: You can report any Purple Dead-Nettle sighting by clicking here.

 

DO:

• Regularly monitor properties for weed infestations.
• Ensure soil and gravel are uncontaminated before transport.
• Check wildflower mixes to ensure that they do not contain Purple Dead-Nettle.
• Ensure that plants are disposed of in a garbage bag if found in floral arrangements to prevent seeds from spreading.

 

DO NOT:

• Do not unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
• Do not plant Purple Dead-Nettle in a garden, no matter how well-contained its enclosure may seem.
• Do not move soil that has been contaminated with Purple Dead-Nettle.
• Do not compost!

 

Control

Mechanical

• Hand-pull before it goes to seed.
• Regular mowing/tilling will reduce weed progression; plant material can be left on site to decompose if the plant hasn’t gone to seed.
• In the post-flowering stage, all plant parts must be bagged and deeply buried in landfills.
• When tilling, be sure to prevent machinery from spreading root fragments to new sites.

Chemical

• Purple Dead-Nettle can be controlled with metsulfuron.
• Fall and early spring applications are generally the most effective and may also suppress seed production.
• We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Biological

No known biological control agents are available for this plant.