Acacia acuminata might be worth looking into, I think it'll go down to as low as -5c for short periods (if established) but can handle 45c in summer. Dmt content of narrow phyllode variant is upwards of 1.2-1.8%.
If you are in a colder region Mt buffalo wattle can survive even colder but is very rare and endangered. Dmt content is lower. It can do a overnight temperatures of -8.5 max and daily temperatures of <1c. Not sure exactlt how cold it can handle, maybe slightly lower? It can handle 38c during summer.
I think the dmt content is reported to be .3% in the phyllodes but i have read young plants may contain 0%. Might be worth reading up on.
Disclaimer: All my posts are of total fiction.