OrnamentalbulbousStraightforward

Crocus

Crocus vernus

Cheap by the hundred, at its best naturalised in grass, and one of the earliest substantial nectar sources of the year — on a warm February day an established drift is loud with bumblebee queens. Squirrels dig the corms up, which is the main obstacle to establishing one.

Position: Full sun or Partial shade
Water: low demand
Drainage: Free-draining
Grows to: 10–15 cm × 5–8 cm
Hardiness: H6
Flowers: February and March
Difficulty: Straightforward

August

Nothing to do

No sowing, planting, harvesting or pruning window falls in August.

Coming next month: plant.

Crocus’s year

Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.

Activity	J	F	M	A	M	J	J	A	S	O	N	D
Plant									September.	October.	November.
In flower		February.	March.

Timing that travels

The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.

Conditions it needs

Light: Full sun, Partial shade
Frost: Very hardy
Hardiness rating: H6 (RHS)
Grows best at: 3–18 °C
Soil: Loam, Sandy, Chalky
Soil pH: 6–7.5
Drainage: Free-draining
Water needs: low
Drought: good tolerance
Waterlogging: poor tolerance
Heat: good tolerance
Wind and exposure: good tolerance

Where these figures come from

LightSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — position
Checked 2026-08-13
FrostSourced guidancehigh confidence: Royal Horticultural Society: Crocus — hardiness
Checked 2026-08-13
Hardiness ratingSourced guidancemoderate confidence: Royal Horticultural Society: RHS hardiness ratings
Checked 2026-08-13
Grows best atSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — temperature
Checked 2026-08-13
SoilSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — soil
Checked 2026-08-13
Soil pHSourced guidancemoderate confidence: Plant Finder — Missouri Botanical Garden: Crocus vernus — culture
Checked 2026-08-13
DrainageSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — soil
Checked 2026-08-13
Water needsHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
DroughtHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
WaterloggingHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
HeatHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Wind and exposureHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

On your soil

Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.

Soil	Verdict	Why
Heavy clay	Works, with one condition	Crocus will crop on heavy clay, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
Sandy	Prefers this soil	Sandy suits Crocus as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. Sandy soil is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Chalky and alkaline	Prefers this soil	Chalky and alkaline suits Crocus as it stands: The free drainage is exactly what it wants. Chalky soil is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Loam	Prefers this soil	Loam suits Crocus as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Silty	Prefers this soil	Silty suits Crocus as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. The soil holds moisture, which saves a great deal of watering.
Peaty and acid	Works, with one condition	Crocus will crop on peaty and acid, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
Shallow over rock	Prefers this soil	Shallow over rock suits Crocus as it stands: The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Made ground and urban soil	Works, with one condition	Crocus will crop on made ground and urban soil, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height: 10–15 cm
Mature spread: 5–8 cm
Rooting depth: 12 cm
Spacing: 5–8 cm apart

Where these figures come from

Mature heightHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Mature spreadHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Rooting depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
SpacingSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — spacing
Checked 2026-08-13

Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

In a container

Minimum volume: 2 litres or more
Minimum depth: 15 cm

Where the container figures come from

Minimum volumeHorticultural consensusmoderate confidence: Royal Horticultural Society: Bulbs in containers
Checked 2026-08-13
Minimum depthHorticultural consensusmoderate confidence: Royal Horticultural Society: Bulbs in containers
Checked 2026-08-13

Excellent in a shallow pan close to a door or a window, which is the only way most people actually see one open — the flowers close in dull weather and a crocus at the bottom of the garden is largely wasted. Gritty compost, planted thickly, and kept out of the reach of squirrels and mice, which take crocus corms in preference to almost anything else.

Habit and ultimate size

What the plant becomes, rather than what it is when you buy it. The gap between the two is where most planting mistakes live.

In a container: Good in a container long-term

Where these figures come from

In a containerHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

All four are sold as 'bulbs'. The differences are internal, which is why they are drawn rather than photographed — and each one changes what you physically do with the thing in your hand.

Storage organ: Corm
Survives winter in the ground: Yes — plant once and leave it
Planting depth: 8–10 cm
Naturalises: Increases and spreads where it is happy

Where these figures come from

Storage organSourced guidancehigh confidence: Royal Horticultural Society: Crocus vernus — propagation
Checked 2026-08-13
Survives winter in the groundSourced guidancehigh confidence: Royal Horticultural Society: Crocus vernus — hardiness
Checked 2026-08-13
Planting depthSourced guidancemoderate confidence: Royal Horticultural Society: Crocus vernus — planting depth
Checked 2026-08-13
NaturalisesHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

A solid swollen stem base, not layered. The old corm is used up each season and a new one forms on top of it, often with small cormlets around the base that take a year or two to reach flowering size.

Two to three times the bulb's own height is the working rule, and the four plants that break it are the four most often planted wrong. A bearded iris buried by mulch or a tidy neighbour will make leaves for years and never flower again.

After flowering. In grass, do not mow for at least six weeks after flowering. The corm is entirely rebuilt each year from what the leaves make, so an early first cut is why a naturalised drift thins instead of thickening.

source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Value to wildlife

Recorded only where the evidence names a resource and the months it is available. Most plants flower; that on its own is not what this section is about.

Nectar: A significant source
Pollen: A significant source
In flower: Feb, Mar

Where these figures come from

NectarSourced guidancemoderate confidence: Royal Horticultural Society: Crocus vernus — value to pollinators
Checked 2026-08-13
PollenSourced guidancemoderate confidence: Royal Horticultural Society: Crocus vernus — value to pollinators
Checked 2026-08-13

What keeping this costs

The value is entirely about timing: on a warm February day an established drift is loud with bumblebee queens, at a point in the year when almost nothing else is open. Mowing a naturalised planting early enough to stop the leaves rebuilding the corm shrinks the drift year on year, and takes that with it.

Where and how you can grow it

Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.

Method	Suitability	What it needs
Open ground	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Container	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13

Growing it

ProtectionCover a new planting with chicken wire pegged down over the soil for the first few months, or plant deeper than the packet suggests. Squirrels find freshly disturbed soil and take crocus corms in preference to almost anything else, and a whole autumn planting can disappear in a week.
PruningIn grass, leave the first mowing until at least six weeks after the crocus flowers have gone over, so the leaves can feed next year's corm. Mowing early is the reason a naturalised drift thins out instead of thickening up.
WateringNo watering at all in open ground, in any season. A crocus corm is a small thing sitting in the top ten centimetres of soil, and the two ways to lose one are waterlogging over winter and damp during its summer dormancy — both of which are drainage problems rather than watering problems. Plant them in ground that does not puddle after rain, and if the only spot available is heavy, add grit into the planting hole or use a pot. Pots of crocus want watering only while the leaves are green in late winter, and want standing dry from May.
FeedingIn a border, a high-potash feed once or twice while the leaves are still green will thicken a clump, but crocuses in grass are the commoner case and there the answer is different: do not feed. Feeding grass feeds the grass, which then outgrows and outcompetes the corms and takes the drift backwards. The thing that actually determines whether a naturalised planting thickens or thins is the mowing date, not the fertiliser — leave it at least six weeks after flowering, because the corm is entirely rebuilt each year from what those leaves make and there is no reserve to fall back on.

Where this guidance comes from

ProtectionSourced guidancemoderate confidence: Royal Horticultural Society: Bulbs — squirrel damage
Checked 2026-08-13
PruningSourced guidancehigh confidence: Royal Horticultural Society: Naturalising bulbs in grass
Checked 2026-08-13
WateringSourced guidancehigh confidence: Royal Horticultural Society: Crocus — cultivation
Checked 2026-08-13
FeedingSourced guidancemoderate confidence: Royal Horticultural Society: Crocus — naturalising
Checked 2026-08-13

The bud you cut to becomes the new shoot, and it grows in the direction it points — which is why an outward-facing bud opens the plant up and an inward-facing one crosses the middle.

What goes wrong

Problem	How often	Notes
Congested bulb clump	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Natural summer dormancy	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13

Sources for this page

GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society

Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.

If something is wrong with it

Leaves yellowing and flopping after flowering — 3 causes GrowingHQ holds for crocus

Something else? Work through it with the diagnostic tool.