But IF you blanch, DO do the whole thing right - like accurate timing (I much prefer steaming), chilling in iced water for the right time, drying, & open freezing at the right temperature before packing.
And then DON'T expect them to last for ever!
I have to say that shop peas are so good these days that we no longer grow our own. And hopefully, being grown in their own packaging, are protected from at least scontact sprays.