Rose of Sharon

Rose of Sharon: how do you recognise it?

Habit

Low, creeping shrub 30–50 cm tall that spreads indefinitely by runners.

Leaves

Elongated oval, 5–10 cm, leathery; dark green above, paler beneath. Turn reddish brown in hard winters.

Flowers

Large, open flowers of 5–8 cm with five golden-yellow petals and a dense brush of long stamens.

Flowering time

From June to September, a few flowers at a time.

Roots

A dense network of roots and underground runners that hold the soil well.

Flowering: June–September · Plants: March–April and September–October · Pruning: March

Why grow it?

• A tough, evergreen ground cover that even grows in dry shade under trees.
• Flowers for a long time, from June into September, with large golden-yellow blooms.
• Bees love to collect pollen from the many stamens.
• Its runners bind slopes and banks well and smother weeds.
• Drought-tolerant and low-maintenance: one cut a year is enough.

Rose of Sharon: where does it grow best?

• Sun, partial shade or shade: it flowers best in sun, and stays a green carpet in shade.
• Almost any soil: sandy, loamy or clay, acid to chalky.
• Dry to average soil; it copes with drought, but not with soil where water stands.
• Ideal under trees, on banks, along paths and where grass will not grow.
• It spreads strongly: do not plant it among delicate perennials in a border.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.4 m tall, 1 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Birch: Light shade above; the yellow flowers look lovely against the white trunk.
• Oregon grape: An evergreen shrub with yellow spring flowers for dry shade.
• Bigroot cranesbill: Another tough ground cover for dry shade, with pink flowers in spring.
• Holly: A dark, evergreen backdrop for the carpet of yellow flowers.

Rose of Sharon: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Clear the ground of weeds, especially perennial weeds such as couch grass and ground elder.
3. Dig a hole a little larger than the root ball and set the plant at the same depth as it was in the pot.
4. Plant 40–50 cm apart, 4–6 plants per m², for a dense carpet within two years.
5. Water in well straight away and keep the soil moist during the first season.
6. Spread a thin layer of wood chips or compost between the plants to suppress weeds until they knit together.

Care

Watering

Only in the first year in dry spells. After that it copes with dry summers.

Feeding

A thin layer of compost after the March cut. Nothing more is needed.

Weeding

Weed regularly in the first year; once the plants have knitted together, weeds stand little chance.

Runners

Every spring, cut back the runners with a spade along paths and borders so it does not go too far.

Cutting back

Every year in March: this keeps the carpet dense and fresh green, and it flowers more.

Tip: Mow or cut it back to 5–10 cm every March. This keeps the carpet dense and fresh, and it flowers more freely.

Rose of Sharon: when to prune it?

Pruning months: March.

When: In March, before the new shoots appear.

How:

• Cut or mow all stems back to 5–10 cm above the ground, with shears or a mower on its highest setting.
• Rake up the clippings, especially if there was rust on the leaves.
• Then add a thin layer of compost.
• There is no need to deadhead in summer.

Caution: Skip the cut for a few years and the carpet becomes woody and bare, and flowering declines.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September: dig up a piece with roots and runners from the edge of the carpet and replant it straight away elsewhere.

Softwood cuttings

In June: 8–10 cm cuttings from non-flowering shoots in moist cutting compost. They root easily.

Rose of Sharon: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: in Belgian gardens it simply stays outside.
• In hard winters the leaves turn reddish brown or partly drop; it reshoots readily in spring.
• No protection is needed; cut off damaged leaves in March along with the rest.

Diseases and pests

• Rust: Orange pustules on the undersides of the leaves, especially in wet summers. Cut the plants back in March and rake up the old leaves.
• Bare, woody carpet: The plants have not been cut back for years. Cut them to 5–10 cm in March; they will reshoot densely.
• Spreading too far: The runners creep into borders or over paths. Cut them back along the edge every spring or install a root barrier.
• Yellow leaves: Often caused by wet, poorly drained soil. Improve the soil or choose a drier spot.

Through the year

• March: Cut back to 5–10 cm. Remove the clippings. Add a thin layer of compost.
• April: Plant or divide. Cut back runners along the edges.
• June: Flowering begins. Take softwood cuttings.
• July: Full flower. Water young plants in dry spells.
• August: Flowering. Watch for rust.
• September: Last flowers. Plant or divide.
• October: Plant.
• December: Evergreen carpet, no work.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• St John’s wort flowers produce no nectar: bees visit them for their abundant pollen.
• One of its English names, Aaron’s beard, refers to the beard-like brush of stamens.
• Thanks to its dense roots and runners, it is often planted to stabilise banks and slopes.