Tall coreopsis

Sun

Full sun; tolerates light shade, but stems may lean and flowering may be reduced.

Water

Water regularly during the first growing season. Established plants tolerate some drought, though flowering is better with occasional deep watering during prolonged dry spells.

Soil

Average, well-drained soil, including clay that does not stay waterlogged. Tolerates relatively poor ground; rich soil can produce floppy growth.

Height

4-8 ft (1.2-2.4 m)

Spread

2-4 ft (0.6-1.2 m), widening over time

Flowers

Late summer to autumn; yellow daisy-like flowers with dark brown centres.

Foliage

Opposite green leaves, usually divided into three narrow, lance-shaped leaflets; lower leaves may have five leaflets.

Growth

Moderate to fast

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   3 ft (0.92 m)

3. After 2 years

   5 ft (1.5 m)

4. After 3 years

   6 ft (1.8 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US and Canada

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Water deeply during establishment, allowing the soil surface to dry between waterings.
• Avoid routine feeding; excess fertility encourages tall, weak stems.
• Apply a thin layer of organic mulch, keeping it away from the crown.
• Support exposed clumps with a discreet ring or neighbouring sturdy perennials before stems reach full height.
• Divide crowded clumps in spring every three to four years, removing unwanted spreading sections.

Pruning. For shorter, bushier plants, cut stems back by about one-third in late spring; this may delay flowering. Leave seedheads standing for birds, then cut dead stems close to the ground in late winter or early spring, or remove spent flowers earlier to limit seedlings.

Late winter

Cut down last year's dead stems before new shoots emerge.

Spring

Plant or divide clumps, water thoroughly, and remove unwanted shoots around established plants.

Late spring

Install supports where needed, or shorten stems by one-third to reduce their final height.

Summer

Water young plants during dry weather; give established clumps a deep soak during prolonged drought.

Late summer

Enjoy flowering and remove spent heads if you want to reduce self-seeding.

Autumn

Leave some seedheads for birds and mark spreading clumps for division next spring.

• Plant at the back of a sunny border for a tall screen of late-season yellow flowers.
• Combine with switchgrass and little bluestem in prairie-style planting for contrasting flower and grass textures.
• Mix with asters and Joe-Pye weed in a large wildlife border to extend the flowering season.
• Use in generous drifts in meadow-style gardens where spreading growth has room to develop.

Garden styles it suits: Native meadow, Midwest prairie, New perennial (prairie), Wildlife garden, Pollinator garden and Cottage garden.

Plant it with: Switchgrass, Little bluestem, New England aster, Joe-Pye weed, Purple coneflower and Blazing star.

Wildlife: Flowers attract bees, butterflies and other pollinating insects. Seedheads provide food for seed-eating birds, including goldfinches in its native range.

• Flopping stems: grow in full sun, avoid rich feeding, and support stems early or shorten them in late spring.
• Powdery mildew: allow space for airflow, avoid drought stress, and remove badly affected fallen foliage.
• Crown or root rot in wet ground: improve drainage or move the plant to a site that does not stay saturated.
• Unwanted spreading and seedlings: remove spent flowerheads before seed ripens and dig out excess rhizomes in spring.

Not known to be toxic to people, cats, dogs or horses. No particular plant part is recognised as poisonous, though species-specific toxicity information is limited and it is not a food plant.

Where it spreads. Can spread assertively by rhizomes and self-seeding in eastern and central North American gardens, especially in moist, fertile soil. It is a native spreader there rather than an introduced invasive plant.

• Prairie coreopsis (Coreopsis palmata)

  Usually much shorter, with leaves deeply divided into three lobes rather than the distinct leaflets typical of tall coreopsis; its flower centres are yellow rather than dark brown.

• Threadleaf coreopsis (Coreopsis verticillata)

  Has finely divided, threadlike foliage and a much lower, bushier habit.

• Cutleaf coneflower (Rudbeckia laciniata)

  Has alternate, broadly lobed leaves and prominent raised greenish flower cones, rather than opposite leaves and relatively flat, dark flower centres.

Coreopsis comes from Greek words meaning bug-like, referring to the seeds' appearance, while tripteris means three-winged and refers to the usually three-part leaves.

Propagation. Divide established clumps in spring. Sow seed outdoors in autumn, or give spring-sown seed a period of cold, moist treatment; seedlings may take until their second year to flower.

Accepted botanical name

Coreopsis tripteris

In the US and Canada

Native in Canada and the lower 48 states.

Sources: GBIF (CC BY 4.0) and USDA PLANTS. The care and design notes are LandscapeGPT's own.