Hi Shireen,

It depends where the grass is growing and what it is growing with. Too much shade as well as over-feeding can both cause a Pampas Grass to withhold flowering. Although they are very hardy they really do need as much heat and particularly as much sun as possible. Also, after a number of years in the same position they get very congested and the centre can die off, at which point you need to cut back hard to about a foot from ground level.

Thank you. I'll try cutting it back and see what happens.