Undergrowth Green vs Alizarin Green

How close are they?

ΔE 8.4, close: similar, with a visible difference side by side. Alizarin Green is more muted than Undergrowth Green.

Can I use Alizarin Green instead of Undergrowth Green?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Alizarin Green is more muted than Undergrowth Green.

Can I use Undergrowth Green instead of Alizarin Green?

The same difference applies the other way round: Undergrowth Green is more saturated.

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.