Download ALIEN PLANT INVADERS: Yellow Archangel Lamium – A Devil To

ALIEN PLANT INVADERS: Yellow Archangel Lamium – A Devil To Control!
A series of articles on how to identify and manage some common invasive species on Salt Spring Island, by
Jean Wilkinson, Stewardship Committee, Salt Spring Island Conservancy (former articles available on SSIC Web-site)
The spread of invasive species is a very serious threat to our native flora and ecosystems, but we can help reduce the
impacts of invasive plants by not planting them and by preventing and controlling infestations in our yards and
neighbourhoods.
In our region one of the most common and challenging invasive plants is Yellow Archangel, aka Dead-nettle. A type of
Lamium native to Europe, Asia, and North Africa, it is often used in hanging baskets or sold as a low maintenance, fastgrowing perennial ground-cover, easily adaptable to sun or shade. This description should trigger alarm bells! Such
plants can quickly take over garden beds and invade nearby natural areas, and they’re difficult to control and remove.
Avoiding this problem by planting non-invasive alternatives (see below) is the best policy, but established patches of
Lamium and other invasive species can be removed with a bit of effort.
Yellow Archangel is particularly problematic as it often spreads into undisturbed wooded areas, forming thick mats and
smothering the native plants that provide habitat for wildlife. Large areas can be severely impacted by the dumping of a
single hanging basket. Other Lamium varieties (eg L. purpureum) also escape gardens, so if you’re set on growing any of
these, please keep them in a contained area, away from the edges of woods or meadows, and be sure to deadhead the
flowers. Never put these plants into the compost or onto a brush pile.
Fall, winter and early spring are perfect times to get rid of Lamium, as it is more easily seen when other plants die down.
In areas that have been completely taken over, replace it with a non-invasive ground-cover or other plants that don’t
threaten the local natural environment.
YELLOW ARCHANGEL LAMIUM– FACTS ABOUT THIS HORTICULTURAL BULLY:
Identification – Lamium galeobdolon. Trailing evergreen perennial groundcover, also climbs up over other vegetation.
Square stems, leaves opposite, slightly hairy, heart-shaped, typically variegated silvery-grey-green. Small
upright yellow flowers in spring produce many seeds.
Impacts –out-competes native vegetation for sunlight and nutrients, and can create large dense mats, killing other plants
and depleting soil fertility.
Found –in forests, woodlands and parks, and along roads, fences and streams, usually near residential areas.
Spreads –stems root easily wherever a node or joint touches the ground, and seeds are widely distributed by ants.
Control – At a minimum, remove spent flowers and dispose carefully to prevent seed formation and dispersal. Cut back
trailing stems to contain plants. To remove plants, start in new or small patches and later move into more
heavily impacted areas. Pull by hand or with pitchfork, making sure to get all the roots out. Try covering large
infestations with builders wrap or tarps held down by mulch until the plants die. Monitor area closely for the
first few months and years following treatment, digging up any new sprouts that appear.
Disposal – Put all plant parts in thick plastic bags and take to landfill or incinerator. Composting is not recommended as
Lamium easily re-sprouts from small pieces, but completely drying plant parts may make them non-viable.
Alternately, dampen all plant parts, put into heavy black plastic bags, seal, place in sunny spot, and turn
occasionally til plants rot and turn to mush. Once absolutely dead, contents can be put into compost pile.
Alternatives – (Note: * indicates plants which are Drought Tolerant when established)
Native Plants: Bunchberry; False Solomon’s Seal; Fringecup; Wild Lily of the Valley; Pacific Bleeding Heart;
Trailing Yellow Violet; Wood Fern; Foam Flower; Heuchera; Piggy-back Plant – Part or Full shade, Moist
Wood Sorrel – Part shade, Moist soil
Twinflower Low Oregon Grape; Deer Fern* – Part shade, Moist or Dry soil
Yerba Buena* – Part shade, Dry soil
Sword Fern; Wild Strawberry* - Sun or Shade, Moist or Dry soil
Red Columbine - Sun or Part shade, Moist soil
Kinnikinnick*; Coastal Strawberry*; Pearly Everlasting* –Sun or Part shade, Dry soil
Yarrow* Woolly Sunflower *– Sun, Dry soil
Non-Invasive Non-natives: Hosta; European Wild Ginger –Part or Full shade, Moist soil
Barrenwort - Part Shade, Moist or Dry soil
Christmas Box – Sun or Shade, Moist soil
More Info - Salt Spring Island Conservancy Stewardship Committee 250-537-4877, Coastal Invasive Species Committee
www.coastalinvasivespecies.com , Invasive Species Council of B.C. www.bcinvasives.ca