ΔE 8.7, close: similar, with a visible difference side by side. Castellan Green is more saturated, cooler than Schilf Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Castellan Green is more saturated, cooler than Schilf Green.
The same difference applies the other way round: Schilf Green is more muted, 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 Schilf Green on the colour wheel See Castellan Green on the colour wheel
All matches: Schilf Green equivalents · Castellan Green equivalents