"thick greenery" is correct and usable in written English.
You can use it to describe lush vegetation or a heavily wooded area. Example: The rolling hills were covered in thick greenery.
Up top, thick greenery gave way to scrub, and a panoramic view of towns and farms below.
The river, about 150 yards across, is undeveloped on the New Jersey bank, and only a smattering of well-spaced small homes on the Pennsylvania side are tucked in the thick greenery.
The thick greenery and fast-flowing streams feel a world away from the dry desert landscape we started from days before, as we make our way up to a vantage point high above sprawling Salta city.
There is thick greenery boxing the road in on all sides, and as the track begins to rise into the mountains and twist around a series of narrow curves, the air temperature drops noticeably.
The federal-style building sits behind an iron gate on a hill thick with greenery.
I made the two-hour drive from Kailua in more or less one fell swoop and landed in the thick, slick, juicy tropical greenery of the Hawaii Tropical Botanical Garden about seven miles north of Hilo.
Above are peaks thick to their summits with greenery.
At first glance, the courtyard of the hotel seems to continue the humid closeness of the rest of the town (claustrophobics, take note): Dimensions seems small, the air thick with chlorophyll from the ever-present overhanging greenery.
The rest of the island comprises a mix of greenery and rocky areas, with the thickest vegetation towards the centre.
The air has been thick with humidity and allergy-inducing pollen from city greenery now convinced it's in a rain forest.
A similar build-up is described by the Dutch golden age painter and art theorist Gerard de Lairesse: 'To paint a festoon, one shall first assign its course and determine how thick or thin it has to be: subsequently the greenery is added, painting the leaves and the foliage, rendering the day side and the shadows according to the light.
