The National Park vegetation is made up of distinct plant communities from the Central System. An important part of them are Guadarrama endemism. The most representative are the Scots pine or Valsaín pine (Pinus sylvestris var. Iberian), the high mountain thickets of broom and creeping juniper, and the xerophyte pastures living on the summits of the Sierra.
In the summits and slopes environment form complex mosaics where alternate wet grass, peat bogs, ponds and lakes, xerophyte pastures, cracks and rocks ledges vegetation communities, etc. This is the growing habitat for the greatest diversity of plant communities and the most unique flora of the territory grow.
In the National Park are represented eight natural systems referred to in the National Parks Law 30/2014.