ΔE 19.2, loose: different enough that you should pick on purpose. Pickle Green is a little darker, more muted, cooler than Undergrowth Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Pickle Green is a little darker, more muted, cooler than Undergrowth Green.
The same difference applies the other way round: Undergrowth Green is a little lighter, more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Undergrowth Green on the colour wheel See Pickle Green on the colour wheel
All matches: Undergrowth Green equivalents · Pickle Green equivalents