It's interesting looking at the Borovets webcam (looking out from the Rila) and the Pamps mid-station webcam; whole both areas still have patches of snow, the Borovets slopes are decidely green while Pamps is just brown mud. Does it get grassy at Studenetz?
Yes it does - but bearing in mind that there is still quite a lot of development going on in the area, the constant up and down of site plant vehicles will make it look very muddy whilst it's still wet.
The slopes are beautiful in the summer with lots of wild flowers, wild raspberries and butterflies. As Pete says though the trucks going up and down tend to churn up some areas.