Does beginning of autumn often water poplars?

Consider it according to your tree species, age and geographical environment.

Poplar likes light. Temperate climate and cold tolerance are required. The requirement for water is very strict, because its photosynthesis and transpiration are higher than those of other broad-leaved trees. Proper watering can promote growth, while excessive watering can lead to rot. You'd better ask the local garden department according to the actual situation.