simple past tense and past participle of cluster
"The old houses were clustered tightly around the town square before the new highway was built."
growing close together but not in dense mats
"The wildflowers were clustered around the base of the old oak tree, leaving open patches of grass between them."
clustered together but not coherent
"an agglomerated flower head"
Grouped into a cluster.
"The colorful flowers were clustered together near the back of the garden, creating a vibrant patch against the green grass."