Clematis 'Niobe'

Sun

Full sun to partial shade; afternoon shade helps in hot climates. Keep the root area cool without shading out the climbing stems.

Water

Keep evenly moist, especially during establishment and flowering. Water deeply when the surface soil begins to dry; avoid waterlogged roots.

Soil

Fertile, moisture-retentive but well-drained soil, from slightly acidic to alkaline.

Height

6-8 ft (1.8-2.4 m)

Spread

2-3 ft (0.6-0.9 m)

Flowers

Large, velvety ruby-red flowers with yellow anthers in late spring and early summer, often followed by a smaller late-summer flush.

Foliage

Green, divided leaves on slender climbing stems; bare in winter.

Growth

Moderate; often takes two or three growing seasons to establish well.

Care needed

Medium

• Pollinators
• Cold hardy
• Low allergen

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

Difficulty

Moderate

Toughness

Fairly tough

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

1. Planting day

   2 ft (0.6 m)

2. After 1 year

   3 ft (0.9 m)

3. After 2 years

   4 ft (1.2 m)

4. After 3 years

   5 ft (1.5 m)

5. After 5 years

   6 ft (1.8 m)

   full size

About 4 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

Toxic

Growth rate

Moderate

• Provide a trellis, wires or mesh with slender sections that the leaf stalks can grip; tie in young stems loosely.
• In well-drained ground, plant the crown about 2-3 in (5-8 cm) below the soil surface.
• Water deeply during dry spells rather than giving frequent light sprinklings.
• Apply compost and a 2-3 in (5-8 cm) mulch in spring, keeping mulch clear of the stems.
• Feed with a balanced fertiliser in spring; for container plants, follow the feed label and check moisture frequently.

Pruning. Usually treated as pruning group 2: in late winter or early spring, remove dead or weak stems and shorten remaining stems to strong live buds. After the first flush, lightly shorten flowered shoots to encourage another flush; hard pruning sacrifices the early flowers.

Late winter

Check supports and lightly prune before strong new growth begins.

Spring

Apply compost, mulch and a balanced fertiliser; guide new shoots onto supports.

Late spring

Check tender shoots for slugs, snails and aphids, and water during dry weather.

Early summer

After the first flowering flush, lightly trim spent flowering shoots if you want to encourage repeat bloom.

Summer

Maintain even soil moisture, particularly in containers, and secure wandering stems.

Autumn

Remove fallen diseased foliage and check that winter rain can drain freely from containers.

• Train over a narrow trellis beside a doorway, where the dark flowers can be seen close up.
• Grow through a pale pink or cream climbing rose for contrasting flowers and shared support.
• Use in a large container with a sturdy obelisk on a patio.
• Clothe a fence panel against pale masonry or foliage, which makes the dark red flowers easier to see.

Garden styles it suits: English country, Cottage garden, Romantic rose garden, Modern courtyard, Small-space and Traditional.

Plant it with: Climbing roses, Hardy geraniums, Lady's mantle, Catmint and Hostas.

Wildlife: The flowers may attract some bees and other insects, though this large-flowered hybrid is not a particularly rich wildlife plant. Its stems can provide light cover when grown through shrubs.

• Clematis wilt can cause sudden stem collapse: cut affected stems back to healthy tissue or ground level, remove debris and protect new shoots from damage; established roots may reshoot.
• Slugs and snails eat emerging shoots: inspect regularly and use barriers, hand-picking or locally approved iron-phosphate bait.
• Aphids cluster on soft growth: wash them off with water and encourage natural predators.
• Dry roots or overheated containers cause wilting and poor flowering: water deeply, mulch the soil and shade the container from strong afternoon sun.

Toxic to cats, dogs, horses and people if eaten. Fresh leaves, stems and other plant parts contain irritating compounds that can cause mouth irritation, drooling, vomiting or diarrhoea; serious poisoning is uncommon because the plant tastes unpleasant. Sap can irritate skin, so wear gloves when pruning.

• Rouge Cardinal clematis (Clematis 'Rouge Cardinal')

  Also has velvety red flowers, but usually flowers mainly from midsummer into early autumn on new growth and is normally hard-pruned as group 3.

• Ernest Markham clematis (Clematis 'Ernest Markham')

  Its flowers are brighter magenta-red rather than the dark ruby red of 'Niobe', and its main display comes later in summer.

Clematis comes from a Greek word for a climbing or trailing shoot, while 'Niobe' refers to the figure of Niobe in Greek mythology.

Propagation. Take softwood cuttings in late spring or early summer, or layer a low-growing stem. Seedlings will not reliably match 'Niobe'.

Accepted botanical name

Clematis

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