Getting it to bloom

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

Also called Benton Susan iris, mid-blue bearded iris, English bearded iris (Iris 'Benton Susan').

More about iris 'benton susan'

About Iris 'Benton Susan'

Iris 'Benton Susan' · also called Benton Susan iris, mid-blue bearded iris · flowering

Iris 'Benton Susan' is a Cedric Morris-bred tall bearded iris with soft lilac-blue ruffled standards and falls touched with bronze beards. It flowers in late spring, thrives in full sun and sharp drainage, and forms slowly spreading rhizome clumps. Like all irises it is toxic to cats and dogs if eaten, the rhizome being most potent.

Plant type: flowering

Watch for — Few or no flowers: Usually from too much shade, overcrowded clumps, rhizomes buried too deep, or excess nitrogen. Divide every 3-4 years and replant rhizomes near the surface in full sun.

The reasons iris 'benton susan' isn't blooming

Almost every non-blooming iris 'benton susan' 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 'benton susan' to flower

Let it get genuinely cold. Leave iris 'benton susan' 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 'benton susan' and get the feeding right with the iris 'benton susan' 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 'Benton Susan' 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 'benton susan' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Iris 'Benton Susan' blooming — frequently asked questions

Why won't my iris 'benton susan' flower?

Iris 'Benton Susan' 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 'benton susan' bloom?

Leave iris 'benton susan' 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 'benton susan' normally bloom?