PARIJAT-HARSINGAR

The tree is sometimes called the “tree of sorrow”, because the flowers lose their brightness during daytime; the scientific parijat flowername arbor-tristis also means “sad tree”. The flowers can be used as a source of yellow dye for clothing. The flower is the official flower of the state of West Bengal, India, and for Kanchanaburi Province, Thailand.

Plant Care:

The greatest enemy of this plant is standing water, which causes the roots to rot and die. Periodic deep watering, well rotted parijat flowercompost, and judicious pruning, is sufficient for this plant and is enough to make it bloom and make your garden beautiful and fragrant.

Fertilising the plants once a year will be beneficial. The plant needs trimming as the shoots grow in different directions. It is better to grow the plant in the shaded area of the garden which receives a few hours of direct sunlight.

Parijat or Harsingar is a winter plant. Keep it away from direct sun in the harshest of summers or its leaves will burn.
It needs a lot of water, often more than other plants. Water it whenever required when soil looks dry. Ensure a steady supply of cow dung manure or compost throughout the year. Keep it in sun when flowering season approaches, around October End - January End. 
Fertilise it or add cow dung/compost to it generously to give it a boost at the beginning of flowering season. If you want to elongate flowering season, remove any spent flowers to avoid seed formation until the end of flowering cycle.
It's a tree so it will do better in the ground than in a pot. Hope this helps.