Penn Museum Blog | Soft Vegetative Roof Capping at Gordion: A Tutorial Video UPDATE

July 30, 2015

This is one in a series of posts about the Gordion ecopark:

Although I am primarily an archaeobotanist, I maintain several gardens at the Penn Museum’s excavation project at Gordion, Turkey. The biggest one is in the large area of the Citadel mound that was excavated down to the 800 BC Early Phrygian level (just before King Midas), between about 1950 and 1971.

Carduus nutans rosettes from last year's seeds grow on the walls, and the purple thistles on the left were last year's rosettes — Carduus nutans rosettes from last year’s seeds grow on the walls, and the purple thistles on the right were last year’s rosettes (photo: N.F. Miller)

Terrace Building 1 wall after weeding (photo: E. Del Bono)

We treat the open-air archaeological site as a specialized kind of garden. It is a work in progress that requires observation and experimentation. The conservation team plants the short perennial, bulbous bluegrass (Poa bulbosa) on the restored, treated walls, but the seeds of other plants blow in. Last summer I posted a video explaining how to manage the vegetation on the restored walls of the site with soft capping. This year I realized it would be cheaper, easier, and more effective to remove only the most harmful plants from the walls: those with deep roots.

Carduus nutans can grow to be a very large plant (photo: N.F. Miller)

Among the most pernicious of these plants is a biennial thistle, Carduus nutans. Here is the video update: