The spicy taste of Polygonum hydropiper comes from the spicy substances in its leaves, stems and flowers, such as capsaicin, gingerol and gingerol. These substances stimulate the oral cavity and gastrointestinal mucosa, causing a spicy feeling.

If the spicy grass you picked is not spicy, there may be the following reasons:

1. The plant is not fully ripe: the spicy grass will accumulate enough spicy substances after it is ripe, and if the picked plant is not ripe enough, it may not be too spicy.

2. genetic differences: different varieties of spicy grass have different genetic characteristics, and some varieties may have less spicy substances, resulting in their taste is not spicy.

3. environmental factors: the growth environment of plants will also affect their spicy degree. For example, the lack of light, water or fertilizer may lead to poor growth of spicy grass, thus affecting the accumulation of spicy substances.

If you want to taste spicy grass, you can try to pick the spicy grass of the elder or pick it when it is fully cooked.