Mugwort (Artemisia vulgaris) is a common perennial herb native to Eurasia but now found throughout much of the world. It is recognized historically as a traditional medicinal and culinary herb, but today it is often known as a persistent and aggressive weed in disturbed landscapes. The plant’s ability to thrive in various conditions and its method of spread are directly linked to the final height it achieves. The ultimate size of mugwort is a primary concern for those managing it in garden beds or agricultural settings.
Defining the Typical Height and Growth Range
The typical height of mugwort falls within a range of two to five feet (60 to 150 centimeters). This upright, herbaceous perennial has stout, angular stems often tinged purplish-brown and covered with fine hairs. Mugwort’s average stature is supported by its growth habit, which tends to form dense, vegetative colonies.
Under optimal conditions, mugwort can reach up to six or seven feet (1.8 to 2.1 meters). This maximum growth occurs in areas with less competition and abundant resources, allowing the stems to elongate significantly before flowering. The plant maintains its vertical structure through the rigidity of these branched, ascending stems, which become somewhat woody as the season progresses.
Environmental Factors Influencing Mugwort Size
Mugwort’s mature size varies widely based on its immediate environment and resource availability. Plants growing in poor, dry soil or those subjected to intense competition are typically shorter, often staying on the lower end of the two-to-four-foot range. These less vigorous specimens dedicate fewer resources to vertical growth, limiting their overall biomass.
The tallest mugwort plants are usually found in full sun exposure and moderately fertile, well-drained soils with medium moisture. Full sunlight maximizes the plant’s photosynthetic capacity, providing the energy needed for rapid stem elongation. A consistent supply of nutrients and water supports the most substantial growth, though the plant tolerates a wide range of soil conditions.
The density of the stand also plays a role, as mugwort often forms thick, monocultural patches that compete for light. In shaded conditions, the stems may “lodge” or flop over as they stretch to find light, preventing them from reaching their maximum potential height. Mugwort thrives in disturbed sites, such as roadsides and waste areas, where the lack of established competitors allows it to dominate and grow unchecked.
Identifying Mugwort and Related Features
Mugwort is identifiable by its distinctive foliage and scent, which help distinguish it from other plants in the Artemisia genus. The leaves are deeply lobed or dissected, giving them a lacy or jagged appearance. A defining characteristic is the stark contrast in leaf color: the upper surface is dark green and relatively hairless, while the underside is covered in dense, silvery-white, woolly hairs.
When the foliage is crushed, it releases a strong, aromatic scent often described as sage-like or similar to chrysanthemum. This fragrance helps distinguish it from related species like Wormwood (Artemisia absinthium), which has silvery hairs on both sides of the leaf. The plant spreads aggressively due to its extensive, branching rhizome system, which is a network of horizontal underground stems. These shallow rhizomes are the primary mechanism for colonization, as they can regenerate a new plant from fragments as small as two centimeters.
Managing Growth and Controlling Spread
Managing the aggressive growth of mugwort requires a persistent, multi-faceted approach due to its robust rhizome system. Simple hand-pulling is often ineffective and can worsen the problem by fragmenting the rhizomes, which then sprout into new plants. Similarly, tilling the soil is not recommended for established patches because it chops the underground roots into numerous regenerative pieces.
Repeated cutting or mowing can suppress the plant, though mugwort is highly tolerant of this method. Mowing throughout the growing season, especially before the inconspicuous flowers produce seed in late summer, can reduce the spread and deplete the plant’s energy reserves. For comprehensive control, integrating chemical methods is often necessary, with herbicides like glyphosate or clopyralid proving effective.
Non-Chemical Control Strategies
Non-chemical control strategies include smothering large patches with heavy-duty landscape fabric or opaque tarps to deprive the plant of sunlight. This technique must be maintained over a long period to starve the rhizomes and weaken the stand. Establishing a dense, competitive cover of desirable plants, such as turfgrass, can also discourage new mugwort establishment by limiting bare ground and resource access.