Offering Doob (Durva) to Ganesh(For fulfilling desires and removing obstacles)
There are a few Mantras, Stotras and Gayatri Mantra related to Lord Ganesh. They all have the power to fulfill the desires of the person and can remove his problems.
Why to offer Durva to Ganesh :-
Besides Ganesh Mantras etc, if a person offers durvaa (Doob), a kind of grass, to Lord Ganesh by Chanting twelve names of Lord Ganesh, his desires are fulfilled and his troubles are removed by the grace of Lord Ganesh.
The twelve names are as follows :-
1. Sumukhaay Namah
2. Ek Dantaya Namah
3. Kapilaay Namah
4. Gaj Karnaay Namah
5. Lambodaraay Namah
6. Vikataay Namah
7. Vighnanaashaay Namah
8. Vinaayakaay Namah
9. Dhoomra Ketave Namah
10 . Ganaadhyakshaay Namah
11. Bhaal Chandraay Namah
12. Gajaananaay Namah