Freezing cannabis is a viable solution for long-term storage if done properly. Cannabis destined for the freezer should be sealed in an airtight package to prevent condensation from collecting, and freezing the plant material (freezer burn).
Be warned also that freezing cannabis will leave the trichomes brittle, and likely to fall off at the slightest touch. This may be fine if you can reliably collect those fallen trichomes in your container, otherwise expect to lose a little potency.