Egeria

Egeria visited Sinai around the year 383. She mentions the Church of the Burning Bush, and the bush itself still alive.

Propterea autem ad caput ipsius vallis exire nos necesse erat, quoniam ibi erant monasteria plurima sanctorum hominum et ecclesia in eo loco, ubi est rubus; qui rubus usque in hodie vivet et mittet virgultas.

We had to come out at the head of the valley for this reason as well, because there are many cells of holy men and a church on the spot where the bush stands; and this bush is still alive today and gives forth shoots.