Autumn crocus vs colchicum
Both flower in autumn straight out of bare ground, and both are sold as autumn crocus. Crocus speciosus is a true crocus: slender violet-blue goblets with darker veins, then grassy leaves, and it multiplies freely. Colchicum is another plant entirely: bigger, top-heavy flowers ('Waterlily' is fully double), big glossy leaves in spring that die down untidily in early summer, and every part is extremely poisonous. Both look best planted through a low groundcover that holds the flowers up.
 Autumn crocusCrocus speciosus |  Colchicum 'Waterlily'Colchicum 'Waterlily' | |
|---|---|---|
| Size | 5 in tall, 3 in wide | 6 in tall, 10 in wide |
| Plant | 3 in apart | 8 in apart |
| Zones | 4 to 8 | 4 to 8 |
| Light | Full sun to part sun | Full sun to part sun |
| Soil | Well-drained, average fertility | Well-drained, average fertility |
| Flowers | Mid September to mid October; lavender, white | Mid September to mid October; pink, lavender |
| Leaves | Fine, summer-dormant | Bold, summer-dormant |
| Job in a bed | Bulb layer | Bulb layer |
| Pets | Toxic (mild) | Toxic (severe) |
| Deer | No record | No record |
| Native | No | No |
| Spread | Moderate risk | Low risk |
Rows where they differ are marked. Flowering times are for zone 5.
Which to choose
- On the record they are near twins: choose by the look you want.
Can they grow together?
Yes: they grow in the same conditions. What colchicum 'Waterlily' brings beside autumn crocus: in flower together for four weeks, from mid September; bold leaves against its fine ones. They share full sun and part sun and zones 4 to 8.
Read more: all about autumn crocus, and all about colchicum 'Waterlily', each with a bed the planner designed around it.