No, the word 'sparsely' is NOT a noun.

The word 'sparsely' is an adverb, a word used to modify a verb, an adjective, or another adverb.

The word 'sparsely' is the adverb form of the adjective 'sparse'.

The noun form of the adjective 'sparse' is sparseness.

May to July is the bloom time of the Lady's Ettercap (Cleistes divaricata).

Specifically, the orchid is a late spring to mid-summer bloomer. The sparseness of its foliage really sets off the delicacy of the plant's bloom. The sole flower is quite noticeable and attractive at the top of the plant's stem.

May to July is the bloom time of the Spreading Pogonia (Cleistes divaricata).

Specifically, the orchid is a late spring to mid-summer bloomer. The sparseness of its foliage really sets off the delicacy of the plant's bloom. The sole flower is quite noticeable and attractive at the top of the plant's stem.