Mouse-ear hawkweed

How to recognise it

Growth habit

Low perennial rosette plant, 5–30 cm tall, with leafy runners above ground that root and form new rosettes, building up dense mats.

Leaf

Oblong to spoon-shaped, 1–7 cm long, untoothed. Upper side green to grey-green with long, scattered white hairs; underside greyish white and felted. Broken leaves ooze white milky sap.

Flower

A single lemon-yellow head 2–3 cm across, made up only of strap-shaped florets, on a hairy, leafless stalk. The outer florets have a reddish stripe underneath. The bracts are covered in small dark hairs.

Fruit/Seed

Small dark seeds topped with a tuft of off-white hairs, carried away by the wind.

Roots

Short rootstock with fine roots. The runners root wherever they touch the soil.

Confusion with

Cat’s-ear has a branched stem with several heads and leaves without white felt. Dandelion has hairless, deeply cut leaves. Other hawkweeds have leafy stems with several heads, and fox-and-cubs, a garden escape, has orange-red heads in a small cluster. Mouse-ear hawkweed: one yellow head per stalk, runners, and leaves with long hairs above and white felt below.

Flowering: May–September · Pruning: September

Why grow it?

• Flowers from May into September and gives nectar and pollen to honeybees, bumblebees, hoverflies and solitary bees, including species that specialise in yellow members of the daisy family.
• Its runners form dense, low mats: a living ground cover for dry, poor spots where grass struggles.
• Copes with drought, trampling and mowing, and survives in poor sand, between paving stones and on old walls.
• An indicator of poor soil: where mouse-ear hawkweed thrives, other flowers of dry grassland feel at home too, such as wild thyme and harebell.
• The flower heads open in sunny weather and close in the evening and in rain, so in short grassland you can watch the flowers follow the weather.

Mouse-ear hawkweed: where does it grow best?

• In the wild on dry, nutrient-poor soil, acid to chalky: thin grassland, heath, dunes, sandy verges, dykes, railway banks and old walls.
• Full sun is a must: in shade and among tall grass it soon disappears.
• Poor, free-draining soil: sand, gravel or stony ground. On rich, moist soil grass quickly grows over it.
• In the garden it suits a thin meadow, a dry rock garden, the gaps between stepping stones, the joints of a patio or a green roof.

Goes well with

• Wild thyme: Flowers at the same time; together they form a low, fragrant mat full of bees.
• Harebell: Blue bells above the yellow heads, on the same poor soil.
• Sheep’s-bit: A plant of the same sandy verges, with sky-blue pompoms.
• Biting stonecrop: A small succulent for the driest corners, yellow in June.
• Sheep’s sorrel: Grows alongside it naturally in thin, acid grassland and adds a russet glow.

Mouse-ear hawkweed: when and how to plant it?

1. Buy plants from a nursery that specialises in native plants, or sow seed of native origin.
2. Sow in September–October or March–April on loosened, poor soil. Press the fine seed in well and cover it with no more than a very thin layer of sand.
3. Plant in March–April or September–October, 20–30 cm apart. After a year or two the runners join up into a mat.
4. Do not enrich the soil: no compost or potting compost in the planting hole. On heavy soil, mix in coarse sand or fine gravel.
5. Water after planting and keep the soil slightly moist for the first few weeks; after that it copes even in dry spells.
6. Never dig up plants from the wild, not even from a verge: buy them or sow your own.

Care

Watering

Only while it establishes. Established plants tolerate long dry spells.

Feeding

Not needed. Fertiliser makes grass stronger, and grass crowds out mouse-ear hawkweed. Poor soil keeps it compact and free-flowering.

Mowing

In a thin meadow, mow once a year in September and remove the cuttings. The flat rosettes even survive a lawnmower, but leave the flower stalks in summer for the bees.

Spreading

In a rock garden or border its runners can smother small plants. Pull out surplus rosettes with their runners; this is easy.

Self-seeding

Leave some of the fluffy seed heads: that way it seeds itself onto small patches of bare ground.

Tip: Want mouse-ear hawkweed in your lawn? Mow a dry, sunny strip less often and remove the cuttings: on poor soil it often turns up by itself, and it stands up to being walked on.

Pruning and mowing

Pruning months: September.

When: In September, after the main flowering, together with the rest of the thin meadow.

How:

• Mow or cut off the spent flower stalks; the leaf rosettes can stay where they are.
• Remove the cuttings so that the soil stays poor and grass does not take over.
• Leave some of the stalks with seed if you want it to spread by seed.
• Cut or pull out runners that stray beyond their place at any time.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Runners

The easiest way: in March–April or September, cut off a rooted rosette with a piece of runner and replant it straight away.

Seed

Sow in autumn or early spring on poor soil, in a tray or where it is to grow. Keep the soil moist until the seedlings appear.

Division

In spring, cut a larger mat into pieces and replant them elsewhere.

Mouse-ear hawkweed: how does it get through the winter?

Hardy to −30 °C.

• Mouse-ear hawkweed is fully hardy, to about −30 °C.
• In winter the leaf rosettes stay grey-green and lie flat against the ground.
• It dislikes wet feet in winter: on heavy, wet soil it can rot.
• The low mats give shelter to small insects and spiders.

Diseases and pests

• Crowded out by grass: On rich soil grass soon grows over it. Mow, remove the cuttings and do not feed.
• Spreading: In a rock garden it can smother small plants. Pull out the runners in good time.
• Rotting: On heavy, wet soil in winter. Plant in a sandy, free-draining spot or mix gravel into the soil.
• Slugs: Slugs sometimes eat young seedlings. Sow or plant in a dry, sunny spot, where they are less common.

Through the year

• March: Plant or divide. Keep small bare patches for seedlings.
• April: New runners grow. Move rooted rosettes.
• May: Flowering begins. Bees and hoverflies on the heads.
• June: Full flower. Do not mow.
• July: Flowering and first seed fluff.
• August: Late flowering. Let seed ripen or collect it.
• September: Mow and remove the cuttings. Sow or plant.
• October: Sow or plant on poor soil.
• December: Rest. The grey rosettes stay visible.

Did you know?

• After his pea experiments, Gregor Mendel also crossed hawkweeds, the group mouse-ear hawkweed then belonged to. The results did not fit his rules, because these plants often set seed without fertilisation.
• The name mouse-ear refers to the small, hairy leaves; the scientific name Pilosella comes from the Latin pilosus, ‘hairy’.
• In New Zealand, where it was introduced, mouse-ear hawkweed has become a troublesome weed of thin grassland. Here it is a native plant that is, if anything, in decline.