We analyse the evolution of scalar field dark energy in the spherical halos of dark matter at the late stages of formation of gravitationally bound systems in the expanding Universe .
The dynamics of quintessential dark energy at the center of dark matter halo strongly depends on the value of effective sound speed c _ { s } ( in units of speed of light ) .
If c _ { s } \sim 1 ( classical scalar field ) then the dark energy in the gravitationally bound systems is only slightly perturbed and its density is practically the same as in cosmological background .
The dark energy with small value of sound speed ( c _ { s } < 0.1 ) , on the contrary , is important dynamical component of halo at all stages of their evolution : linear , non-linear , turnaround , collapse , virialization and later up to current epoch .
These properties of dark energy can be used for constraining the value of effective sound speed c _ { s } by comparison the theoretical predictions with observational data related to the large scale gravitationally bound systems .