Getting it to bloom

Why won't my Iris 'Immortality' bloom? (and how to make it flower)

Also called Immortality iris, white reblooming iris, rebloomer iris (Iris 'Immortality').

More about iris 'immortality'

About Iris 'Immortality'

Iris 'Immortality' · also called Immortality iris, white reblooming iris · flowering

Iris 'Immortality' is a reblooming tall bearded iris with pure ruffled white flowers and pale lemon beards, flowering in late spring and often again in late summer or autumn. Grow in full sun and sharply drained soil with rhizomes near the surface. Reaching about 75 cm, it is fragrant and reliably repeat-blooming in warm regions.

Plant type: flowering

Watch for — Failure to rebloom: Cold climates, shade, crowding or under-feeding prevent the second flush. Site in full sun, feed through summer and divide regularly to encourage rebloom.

The reasons iris 'immortality' isn't blooming

Almost every non-blooming iris 'immortality' traces back to one of these, roughly in order of how common they are:

Bulbs were not chilled long or cold enough (a problem in mild winters or with un-chilled forced bulbs).
The winter was too mild or the plant too sheltered to bank enough chill hours.
Foliage was cut down too early last year, so the bulb could not recharge for this year’s bloom.
Too little sun during the growing season to build the reserves the flower needs.
Excess nitrogen feed driving leaf at the expense of flower.

Skipping the cold period (or buying un-chilled bulbs in a mild climate). Without real vernalisation there are no flowers.

The fix — how to get iris 'immortality' to flower

Let it get genuinely cold. Leave iris 'immortality' outdoors (or in an unheated, cold spot) through winter — do not mulch heavily or shelter it from the cold it needs.
Chill the bulbs properly. Use pre-chilled bulbs, or give 12-16 weeks of cold (around 4-9 °C / 40-48 °F) before planting in mild climates.
Feed the foliage, then leave it. Let leaves grow and feed the plant after flowering; never cut foliage down until it yellows naturally.
Be patient after any move. Expect a settling year (or two to three for peony) with few or no flowers after planting or division — this is normal, not failure.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for iris 'immortality' and get the feeding right with the iris 'immortality' fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Iris 'Immortality' flowers in its season (typically spring for chilled bulbs) once the cold requirement is met, then dies back to recharge for next year.

Post-bloom care so it flowers again

Let the foliage die back fully before tidying — it is recharging the bulb. A light feed after flowering supports next year's display.

For everything else this plant needs day to day, see the full iris 'immortality' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Iris 'Immortality' blooming — frequently asked questions

Why won't my iris 'immortality' flower?

Iris 'Immortality' needs a real cold period (vernalisation) to flower — the winter chill is the signal that ripens the bud inside the bulb or crown. The most common reason it is not happening: Bulbs were not chilled long or cold enough (a problem in mild winters or with un-chilled forced bulbs).

How do I make iris 'immortality' bloom?

Leave iris 'immortality' outdoors (or in an unheated, cold spot) through winter — do not mulch heavily or shelter it from the cold it needs. Use pre-chilled bulbs, or give 12-16 weeks of cold (around 4-9 °C / 40-48 °F) before planting in mild climates.

When does iris 'immortality' normally bloom?