Wine · Terminology
Flowering
When the vine's tiny flowers open and self-pollinate — six to thirteen weeks after budburst.
Flowering happens six to thirteen weeks after budburst, when the vine's inflorescences open into small, unshowy green-white flowers. Vines are self-pollinating — no bees required — and each flower that is fertilised becomes a grape.
Flowering is the single most weather-sensitive moment of the season. It needs warm, dry, still conditions over one to two weeks. Cold, wet or windy weather disrupts pollination and the crop is reduced before it has begun, which is why growers watch the forecast in June with more anxiety than at any other time except harvest.
In practice
- Poor flowering weather causes two classic problems: coulure (flowers fail to set and drop) and millerandage (uneven berries, some seedless and tiny — "hen and chicken").
- Both cut yield, but millerandage can raise quality: small, seedless berries give a high skin-to-juice ratio.
- Flowering date is also a harvest predictor — roughly 100 days from flowering to picking, depending on variety and climate.
- Varieties differ in susceptibility: Grenache and Merlot are notoriously prone to coulure.
Where you'll meet it
- Vintage reports, which almost always open with flowering conditions.
- The growing cycle guide.
- Any explanation of why one vintage produced half the wine of the next.
Coulure and millerandage
| Coulure | Millerandage | |
|---|---|---|
| What happens | Flowers or young berries drop | Berries set unevenly, many stay small and seedless |
| Cause | Cold, wet or windy flowering; vine stress | Same conditions, plus boron deficiency and fanleaf virus |
| Yield | Sharply reduced | Reduced |
| Quality | Neutral to negative | Often positive — concentration |
| Prone varieties | Grenache, Merlot, Malbec | Chardonnay, Gewurztraminer |
Why the timing matters
An early flowering points to an early harvest, and an early harvest usually means picking in warmer conditions — which affects acidity, sugar and picking logistics. Growers use the flowering date as their first real estimate of both volume and harvest window, and it drives everything from labour booking to tank space.