D.S. Clarke states that panpsychist elements can be found in various Buddhist sects, such as Huayan and Tiantai/Tendai Buddhism. The Tiantai patriarch Zhanran says “even non-sentient beings have Buddha nature.”
“Who, then, is “animate” and who “inanimate”? Within the assembly of the Lotus, all are present without division. In the case of grass, trees and the soil…whether they merely lift their feet or energetically traverse the long path, they will all reach Nirvana.”
The Japanese Buddhist Saicho likewise spoke of “buddha-nature of trees and rocks” and the 9th-century Shingon Buddhist thinker Kukai speaks of natural and inanimate objects as rocks as included in the Buddha’s supreme embodiment. Likewise, Dogen, my favorite Zen Buddhist, stated that “fences, walls, tiles, and pebbles” are also “mind…insentient beings expound the teachings” and said that the teaching of the Buddha as “engraved on trees and on rocks . . . in fields and in villages”.
Clarke, D.S. Panpsychism: Past and Recent Selected Readings. State University of New York Press, 2004.