Getting it to bloom

Why won't my Showy Autumn Crocus bloom? (and how to make it flower)

Also called Showy autumn crocus, Giant meadow saffron, Showy colchicum (Colchicum speciosum).

More about showy autumn crocus

About Showy Autumn Crocus

Colchicum speciosum · also called Showy autumn crocus, Giant meadow saffron · flowering

Showy autumn crocus is a large-flowered cormous perennial native to subalpine meadows of northern Turkey, the Caucasus, and northern Iran, producing impressively large, goblet-shaped flowers up to 12 cm across in shades of rosy-purple to white from August to October. It is the parent of many popular garden colchicum cultivars and is considered one of the finest and most showy of all autumn-flowering bulbs. Plant the large corms during summer dormancy in well-drained soil where the tall flowers will not be obscured by neighbouring plants. All parts of this plant contain colchicine and are extremely toxic to pets and humans.

Plant type: flowering

Watch for — Flower stem collapse (lodging): The tall, naked flower stems can flop in windy or exposed sites; plant in a sheltered position or adjacent to low groundcover plants that support the stems without obscuring the large blooms. Avoid high-nitrogen soils which produce soft, weak stems.

The reasons showy autumn crocus isn't blooming

Almost every non-blooming showy autumn crocus 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 showy autumn crocus to flower

Let it get genuinely cold. Leave showy autumn crocus 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 showy autumn crocus and get the feeding right with the showy autumn crocus 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

Showy Autumn Crocus 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 showy autumn crocus care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Showy Autumn Crocus blooming — frequently asked questions

Why won't my showy autumn crocus flower?

Showy Autumn Crocus 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 showy autumn crocus bloom?

Leave showy autumn crocus 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 showy autumn crocus normally bloom?