The time of day you catch "Knotweed" will affect how you feel about it.
"Knotweed" is rain tapping at the window, grey skies over the country side, an introspective afternoon; it's returning home after a long trip; it's leaving a relationship after a long struggle.
For me, it's waking up after a strange dream, a lingering feeling that I can't seem to touch with words, but this tune by Laurence Guy is voicing my mood just fine.
Whatever your environment, wherever your mind -- enjoy.