Red moon (lune rousse)
The lune rousse is, in French rural tradition, the lunation that begins just after Easter, roughly between late April and late May. Its name comes from the belief that its light scorches young shoots. In reality the damage comes from late frosts on clear spring nights, not from the Moon: a folk concept grafted onto a very real weather phenomenon.
Where the name comes from
Old gardeners dreaded this lunation for their fragile seedlings: browned leaves, buds burnt the morning after a clear night. With no explanation at hand, the moonlight was blamed for scorching the shoots, and the name stuck. The lune rousse is therefore not a color of the Moon, but a period in the farming calendar.
What actually happens
On clear nights this season, with no clouds to hold the heat, the ground cools sharply by radiation and the temperature can drop below zero before dawn. It is these white frosts that harm young leaves. The Moon only marks the risky season: it is a cue, not a cause. Sheltering seedlings on clear nights is enough, no superstition required.