Flower · Asparagaceae
When to sow hyacinths
Grown for scent more than for looks - a dozen bulbs will fill a garden with it. The dense first-year spike loosens into something more graceful in later years, which some gardeners prefer and others replant to avoid.
Days to maturity
150-200
From sowing to a first picking.
Hardy in USDA zones
4a to 8a
Winter cold sets the limit here, not the calendar.
Frost tolerance
Very hardy
How much cold the plant itself will take.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Hyacinths are anchored to the first autumn frost rather than the last spring one, so the useful offset runs backwards from the end of the season instead of forwards from its start.
- Expect 150–200 days to maturity, counted from sowing.
- Hardy in USDA zones 4a–8a.
- Can also be sown in late summer for an autumn crop or to overwinter.
Getting the timing right
Plant four to six weeks before the first autumn frost, 12cm deep. For flowers indoors at midwinter, pot prepared bulbs in early autumn and give them ten weeks somewhere dark and around 9C before bringing them into warmth - rushing that cold period is the usual reason a forced hyacinth flowers down inside its leaves.
Frost tolerance
Hardy to about -25C in the ground. Requires roughly thirteen weeks below 9C, so it is one of the first bulbs to fail in a mild winter. The bulbs irritate skin; handle them with gloves.
Classified as very-hardy, with damage expected below -25°C (-13°F)-13°F (-25°C).