Iris pseudacorus 'Bastardii' (pale yellow iris) — Clump-forming, upright

Overview

Iris pseudacorus 'Bastardii' is a clump-forming, upright perennial in the genus Iris, part of the Iridaceae family, with deciduous or evergreen; sword-shaped to grassy, often glaucous foliage. It typically grows around 1.5 m tall. Iris pseudacorus 'Bastardii' grows best in full sun; some tolerate partial shade, and tolerates loam and chalk or sand; sharply drained for bearded kinds soils and neutral to slightly alkaline pH. Its UK hardiness is rated H5–H7. It is native to Europe.

About

Iris pseudacorus 'Bastardii' is a clump-forming, upright perennial reaching about 1.5 m, notable for its sword-shaped, often glaucous foliage. It flowers in the UK from May to July. Plants suit a sunny, south- or west-facing spot in neutral to slightly alkaline soils. Wear gloves and other protective equipment when handling because the plant is harmful if eaten.

Wikipedia contributors, CC BY-SA 4.0 — Iris pseudacorus

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 pseudacorus 'Bastardii' is a European iris with an upright, clump-forming habit and long, sword-like leaves that often show a glaucous bloom. It typically reaches about 1.5 m and flowers in the UK from May to July. The genus is established across temperate Europe, and this cultivar retains the structural foliage that carries through the season. Plant into loam, chalk or sandy soils with a neutral to slightly alkaline pH, choosing a south- or west-facing position where plants receive full sun (they will tolerate some partial shade). Ensure soil is reasonably free-draining; the genus generally prefers well-drained conditions, while specific bearded types are best in sharply drained mixes. Rated H5–H7, this iris is hardy to very hardy and is suitable for most UK gardens where winter temperatures fall within those bands. Stand the clumps where their upright leaves can provide vertical structure at the back of a border or at the edge of a planted water feature margin if the situation still matches the prescribed soil conditions. Take care when handling and avoid ingestion: the plant is harmful if eaten, and gloves and protective equipment are recommended; for pet-safety guidance consult the HTA guide to potentially harmful plants.

Growing conditions

Best soil and position for Iris

Sunlight: Full sun; some tolerate partial shade
Soil type: Loam, chalk or sand; sharply drained for bearded kinds
Soil pH: Neutral to slightly alkaline
Soil moisture: Well drained; Siberian and Japanese kinds need moisture-retentive soil
Aspect: South or west facing
Exposure: Exposed or sheltered
UK hardiness: H5–H7

Plant details

Iris pseudacorus 'Bastardii' size, habit and characteristics

Plant type: Perennial
Habit: Clump-forming, upright
Foliage: Deciduous or evergreen; sword-shaped to grassy, often glaucous
Height: 1.5 m
Native to: Europe
Toxicity: Harmful if eaten. Wear gloves and other protective equipment when handling. Pets: Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants

Care notes

Pruning and caring for Iris pseudacorus 'Bastardii'

Cultivation: Plant bearded irises with the top of the rhizome exposed so it can bake in summer sun; beardless kinds sit just below the surface in richer, damper ground. Feed with a low-nitrogen fertiliser after flowering and keep the rhizomes clear of mulch and encroaching neighbours.
Pruning: Remove spent flower stems at the base. Trim the outer leaves back by about half in late autumn to reduce overwintering fungal spores, leaving the central fan intact.
Propagation: Divide rhizomes six to eight weeks after flowering, discarding the old woody centre and replanting vigorous outer sections. Species come from seed, but named cultivars will not come true.
Pest resistance: Generally trouble-free, though iris sawfly and slugs damage foliage and thrips can disfigure buds.
Disease resistance: Prone to leaf spot, and to rhizome rot wherever drainage is poor or planting too deep.

Frequently asked questions

How do I grow Iris pseudacorus 'Bastardii'?

Plant bearded irises with the top of the rhizome exposed so it can bake in summer sun; beardless kinds sit just below the surface in richer, damper ground. Feed with a low-nitrogen fertiliser after flowering and keep the rhizomes clear of mulch and encroaching neighbours.

Where is the best place to plant Iris pseudacorus 'Bastardii'?

Iris pseudacorus 'Bastardii' prefers full sun; some tolerate partial shade. It suits exposed or sheltered positions.

What soil does Iris pseudacorus 'Bastardii' need?

Iris pseudacorus 'Bastardii' grows best in loam and chalk or sand; sharply drained for bearded kinds soil. It prefers neutral to slightly alkaline soil. Aim for soil that stays well drained; siberian and japanese kinds need moisture-retentive soil.

How do I prune Iris pseudacorus 'Bastardii'?

Remove spent flower stems at the base. Trim the outer leaves back by about half in late autumn to reduce overwintering fungal spores, leaving the central fan intact.

How big does Iris pseudacorus 'Bastardii' grow?

Iris pseudacorus 'Bastardii' reaches a height of 1.5 m.

Is Iris pseudacorus 'Bastardii' hardy in the UK?

Iris pseudacorus 'Bastardii' has an RHS hardiness rating of H5, meaning it is hardy in most of the UK, tolerating -15 to -10°C.

How do I propagate Iris pseudacorus 'Bastardii'?

Divide rhizomes six to eight weeks after flowering, discarding the old woody centre and replanting vigorous outer sections. Species come from seed, but named cultivars will not come true.

Is Iris pseudacorus 'Bastardii' toxic?

Harmful if eaten. Wear gloves and other protective equipment when handling. Pets: Harmful if eaten. For further information and contact numbers regarding pets, see the HTA guide to potentially harmful plants.

More in the Iris genus

Browse all Iris →