Overview

Iris sibirica 'Tropic Night' is a clump-forming perennial in the genus Iris, part of the Iridaceae family, with sword-shaped foliage. It typically grows around 0.6 m tall and 0.3 m wide. Iris sibirica 'Tropic Night' grows best in full sun, and tolerates loam soils and neutral pH. Its UK hardiness is rated H7. Suggested uses include borders, rock gardens and containers. It is native to Europe and Western Asia.

About

Iris sibirica 'Tropic Night' is a clump-forming perennial in the Iridaceae grown for its upright, sword-shaped leaves and mid-summer flowering. It blooms from May to July. Plant in full sun on a neutral loam that drains well, ideally on a south-facing, sheltered site. Suitable for borders, rock gardens and containers, where the foliage provides vertical structure.

About the genus

Iris takes its name from the Greek goddess of the rainbow, and for once the naming feels entirely earned. I can't think of another genus that covers so much ground — inky purples, burnt apricots, clean whites, blues that seem lit from inside — or so many situations. There are bearded irises that want their rhizomes baked in full sun, Siberian types happy in ordinary border soil, and species that will sit contentedly at the edge of a pond. What they share is the flower: three petals standing up, three falling away, built with a kind of architectural confidence most plants never attempt. Even out of bloom the foliage earns its place — those upright fans of blue-green leaves hold a border together for months. I grow them for the fortnight in May and June when nothing else in the garden can compete, and I've made my peace with that. Some plants are for the long haul. An iris is an event.

Written by Henry

In the garden

Iris sibirica 'Tropic Night' is a clump-forming iris with pronounced sword-shaped foliage and a defined mid-summer flowering season (May to July). As a member of the Iridaceae it presents a clear vertical habit that suits mixed perennial edges and contained groups. Position the plant in full sun on a neutral loam that drains freely; a south-facing, sheltered aspect reduces wind damage and helps flower stems hold up. Hardiness is H7 (fully hardy in the UK), so it tolerates winter conditions commonly experienced across the country. Ensure soil is well-drained — free waterlogged conditions are the main risk to crown health. Use Iris sibirica 'Tropic Night' in the back of borders where the upright leaves add structure, in rock garden pockets with deeper loam, or planted in containers for a sunny patio. Its combination of persistent sword-like leaves and a clear May–July bloom period gives summer rhythm to plantings, with the foliage continuing to define the bed once flowers fade.

Growing conditions

Best soil and position for Iris

Sunlight

Full sun

Soil type

Loam

Soil pH

Neutral

Soil moisture

Well-drained

Aspect

South-facing

Exposure

Sheltered

UK hardiness

H7

Plant details

Iris sibirica 'Tropic Night' size, habit and characteristics

Plant type

Perennial

Habit

Clump-forming

Foliage

Sword-shaped

Height

0.6 m

Spread

0.3 m

Suggested uses

Borders, rock gardens, containers

Native to

Europe, Western Asia

Care notes

Pruning and caring for Iris sibirica 'Tropic Night'

Cultivation

Plant in full sun on neutral, well-drained loam. Divide clumps every 3-4 years in spring or autumn to maintain vigor.

Pruning

Cut back foliage to ground level after flowering or in late autumn to tidy the plant.

Propagation

Division, seed

Pest resistance

High

Disease resistance

High

Frequently asked questions

More in the Iris genus

• 
  Iris 'Antigone' (TB)
• 
  Iris 'Dauntless' (TB)
• 
  Iris 'Dipped in Dots' (TB)
• Iris 'Ablaze' (MDB)
• Iris 'After the Storm' (TB)
• Iris 'Aldo Ratti' (TB)
• Iris 'Alene's New Love' (SDB)iris 'Alene's New Love'
• Iris 'Alpine Lake' (MDB)