The Hahaki tree was a legendary plant reputed to grow at Sonowara on the border between the provinces of Shinano and Mino (modern day Nagano and Gifu prefectures). The magical property of this plant was that it could only be seen from a distance: the closer you got to it the more difficult it was to see until it vanished completely. Hence Korenori is saying that he is only able to worship his lady from a distance–a face-to-face meeting is out of the question.