At a Glance
TypePerennial
HabitSpreading
FoliageSemi-evergreen
Height1-10 inches (2.5-25 cm)
Width12-24 inches (30-60 cm)
Maturity1 years
Key Features
Maintenancevery low
Overview
Pilosella pilosella (syn. Hieracium pilosellum) is a low-growing, stoloniferous perennial in the Asteraceae family, forming dense mats of basal rosettes 1–4 inches (2.5–10 cm) tall, spreading by above-ground stolons (runners) to cover 12–24 inches (30–60 cm) or more per plant. Leaves are spatulate to oblanceolate, 1–4 inches (2.5–10 cm) long, dark green above and white-felted beneath, with long, stiff, white hairs on the upper surface — the hairs give the leaves a furry texture that accounts for the "mouse-ear" common name. Flower stems (scapes) are leafless, 4–10 inches (10–25 cm) tall, bearing a single composite flower head 0.75–1 inch (2–2.5 cm) across composed entirely of pale lemon-yellow ray florets. The undersides of the outer ray florets are often streaked with red. Flowers close on overcast days and in the evening. Seeds are produced apomictically (without fertilisation) in most populations, creating genetically identical daughter plants. The species is native to Europe but is classified as a serious invasive weed in New Zealand, Australia, and parts of North America (particularly the Pacific Northwest and the northeastern states), where it invades lawns, meadows, and disturbed grassland, forming dense monocultures that exclude native vegetation. The stoloniferous habit enables rapid lateral spread — a single plant can colonise several square feet per season. In the Pacific Northwest, it is listed as a noxious weed in several counties.
Native Range
Pilosella pilosella is native across Europe, from the British Isles and Scandinavia south to the Mediterranean and east through western and central Asia. It occurs in dry grasslands, rocky slopes, road verges, and open habitats from sea level to approximately 8,500 feet (2,600 m).Suggested Uses
In its native European range, P. pilosella occurs naturally in dry meadows and is a component of species-rich calcareous grassland. In North America and the Pacific Northwest, it is treated as an invasive weed rather than a garden plant. Not recommended for intentional planting in the Pacific Northwest. In European alpine gardens and green roof systems, the mat-forming habit and drought tolerance have limited specialised application on very poor, thin substrates where spread can be contained.How to Identify
Appearance
Size & Dimensions
Height1" - 10"
Width/Spread1' - 2'
Reaches mature size in approximately 1 years
Bloom Information
Flower heads open from May through August, with peak bloom in June. Each head lasts 3–5 days. Scapes are produced continuously over the summer from actively growing rosettes. Apomictic seed is set without pollination in most populations. Seed heads form a small pappus for wind dispersal.Detailed Descriptions
Foliage Description
Dark green above, white-felted beneathGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight