Identification and Reproduction

Identification:

• Yellow archangel is an aggressive growing perennial ground cover plant. Depending on conditions it can be trailing or upright. 
• Square, hairy stems. When growing horizontally they can extend up to 60 cm tall. 

• Leaves are opposite, serrated and oval- to heart-shaped; can range from 2.5-8 cm long.  Upper sides are hairy and variegated (i.e., have a silver or white pattern).
• Flowers are bright yellow, small and tubular. Flowers grow in pairs of clusters whorled around the stems at the leaf axils. Flowering occurs between April and June.

Reproduction:

• Typically will spread vegetatively by stems and rooting at the nodes. 
• Roots can extend 20 cm deep into the soil. 
• Each flower will contain four nutlets, each of these nutlets will bear a viable seed. They may be dispersed by ants that can transport them up to a distance of 70 meters.
• This groundcover plant is capable of climbing over stumps and other ground obstacles. 

Habitat & Ecology

• Tolerates a wide range of light, pH, organic level and drainage conditions. 
• Adapted to growing in shaded and open areas but does best in moist, shaded sites and often grows in natural forested areas adjacent to urban and residential neighbourhoods. 

Impacts

Ecological: 

• It is commonly found in hanging baskets and garden beds. When improperly disposed of in greenspaces, will form dense mats across the forest floor.
• Yellow lamium reduces natural biodiversity by smothering native herbs, shrubs and even mosses.
• Its continuous cover also suppresses the growth of natural tree seedlings.  

Management

Mechanical/Manual Control:

• Lamium can be hand-pulled quite easily but can be time consuming if it covers a large area. Minimize the amount of stem and root fragments left behind, as these may regrow. 
• Avoid composting, plants should be bagged and disposed at the landfill. 
• Make sure to replant the area with native shrubs to provide competition and follow-up for several seasons.
• Sheet mulching is also effective - instructions can be found here.

For alternative planting options to yellow lamium download the ISCBC's Grow Me Instead brochure (pg. 57 and 58).

Resources

Download the Invasive Species Council of BC's TIPS Factsheet on Yellow lamium here.

Download the Metro Vancouver Factsheet on Yellow lamium here.

For further details on Yellow Archangel control please refer to the Metro Vancouver Best Management Practices for Yellow Archangel (pg. 11-18)

Header photo (Rotorua Ecological District).