Question

The jute plant is normally harvested when it is at flowering stage

Answer 1

Your statement is correct. But your question isn't stated.
If you're asking about retting of fibres-
After harvesting jute, it is kept submerged in water for a few days. During this period, the stem of the plant rots and the fibres (present in the stem) remain. The process by which fibres are obtained from the stem of the plantis known as Retting .

Answer 2

Answer:

flowering stage

The jute plant is normally harvested at flowering stage. The stems of harvested plants are bundled and immersed in water for 10 to 15 days. The stems rot (the process is called rotting) and fibres are separated by hand.