Autumn crocus
Crocus speciosus ·
A true crocus that flowers in autumn: violet-blue goblets with darker veins and orange stigmas, appearing before the leaves.
- Size
- 5 in tall, 3 in wide
- Zones
- 4 to 8
- Light
- Full sun to part sun
- Flowers
- Mid September to mid October
- Pets
- Toxic (mild)
- Job in a bed
- Bulb layer
A bed built around autumn crocus
The planner designed this bed around autumn crocus when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why autumn crocus stands where it does.
The plants
- 1 Moor grass 'Greenlee' × 6, tan
- 2 October daphne × 3, pink
- 3 Sneezeweed × 3, yellow
- 4 Wild quinine × 5, white
- 5 Inkberry 'Gem Box' × 1, dark green leaves
- 6 Iceland poppy × 5, orange
- 7 Autumn crocus × 12, lavender
- 8 Star of Persia × 5, purple
Why this plant
- The only lavender.
Why here
- In the middle. At 5 in it stands ahead of wild quinine (3½ ft) without hiding it.
- 12 plants in 2 handfuls. In the gaps between other plants, which fill the space when the bulb is not in growth.
Why now
- In flower for five weeks. From mid September to mid October.
- In company. With October daphne and sneezeweed in mid September: 3 kinds at once.
- Leaves gone by midsummer. They die back and leave bare ground. A perennial that comes up late stands beside it, and grows over the gap.
Planned as a cottage garden: 23 of the 23 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. The flowering is at its height in late June, with 4 kinds out together. Moor grass 'Greenlee' and inkberry 'Gem Box' carry the bed through winter.
The planner's own design check: 12 Excellent, 5 Good. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where autumn crocus goes in a border
At 5 in it belongs at the front of a bed. In the planner's ten height classes it is ground-hugging (up to 6 in).
Its job: bulb layer. Small bulbs planted in handfuls of five or seven in the gaps between other plants, for colour before the perennials wake up.
The easiest autumn-flowering crocus, and it multiplies readily. Plant it through a low groundcover, which holds up the slender flowers in rain.
- Autumn colour at ground level
- Naturalising in grass
- Through low groundcover
What to plant with autumn crocus
Plants recorded as good partners for it, and what each pairing does:
- Leadwort: in flower together for three weeks, from mid September; grows up in time to hide its dying leaves; tall enough (10 in) to stand behind it.
- Creeping thyme: flowers first, early June to mid July, so the spot is never empty.
- Sedum 'Dragon's Blood': flowers first, late June to early August, so the spot is never empty.
Questions about autumn crocus
Does autumn crocus need sun or shade?
Autumn crocus grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).
It wants ordinary well-drained soil, of average fertility, and little watering once settled.
What zones does autumn crocus grow in?
USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does autumn crocus flower in my zone?
In zone 5 it flowers mid September to mid October. As an autumn flower it keeps much the same dates in every zone: it answers to shortening days and cool nights more than to the warmth of spring.
| Zone 4 | Mid September to mid October |
|---|---|
| Zone 5 | Mid September to mid October |
| Zone 6 | Mid September to mid October |
| Zone 7 | Mid September to mid October |
| Zone 8 | Mid September to mid October |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should autumn crocus be planted?
3 in (8 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 5 in (12 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many autumn crocus plants do I need?
At 3 in apart, set out in staggered rows:
- 168 to fill 10 square feet (about 1 m²)
- 39 for a single row 10 ft (3 m) long
- 536 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as handfuls of five or seven, in the gaps between other plants.
In the bed above, the planner used 12 in two groups.
Is autumn crocus poisonous to dogs and cats?
Yes: mild toxicity to dogs and cats. May cause mild stomach upset if eaten. This is a true crocus, not the highly poisonous meadow saffron (Colchicum).
Is there a pet-safe plant like autumn crocus?
These come closest to doing what autumn crocus does, and no toxicity is recorded for them:
- Striped squill: the same job in a bed and the same size; flowers late March to mid April, blue, not lavender.
- Spring starflower: the same job in a bed and the same size; flowers early April to early May, blue or white, not lavender.
- Grape hyacinth: the same job in a bed and the same size; flowers mid April to early May, blue, not lavender.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Will autumn crocus spread?
It seeds itself about; the risk of it taking over is moderate. Multiplies by offsets and seed and spreads through a bed over time. It is easy to lift where it is not wanted.
What can I plant to hide autumn crocus's leaves after it flowers?
A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:
- Lady's mantle: 18 in tall and 24 in wide, in flower late May to early July.
- Catmint 'Walker's Low': 24 in tall and 2½ ft wide, in flower mid May to mid September.
- Garden chrysanthemum: 24 in tall and 24 in wide, in flower mid September to late October.
What does autumn crocus look like in winter?
Autumn crocus is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.
More Crocus
- Crocus Crocus vernus
- Crocus 'Ruby Giant' Crocus tommasinianus 'Ruby Giant'
- Early crocus Crocus tommasinianus
- Saffron crocus Crocus sativus
- Snow crocus Crocus chrysanthus
In these guides
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Plants that flower in fall
- Plants for a white garden
Every fact on record
- Type
- Bulb
- Size
- 5 in (12 cm) tall, 3 in (8 cm) wide
- Plant
- 3 in (8 cm) apart
- Height class
- Ground-hugging (up to 6 in)
- Place in the bed
- Front
- Flowers
- Mid September to mid October; open bowls; lavender, white
- Leaves
- Fine texture, summer-dormant; green
- Shape
- Upright, self-seeding
- Hardy in
- USDA zones 4 to 8
- Light
- Full sun, part sun
- Soil
- Average, well-drained
- Water
- Low
- Feeding
- None needed
Not yet checked against an outside reference: its figures rest on general horticultural knowledge. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.