Like may western species, I.trilobus is not regarded as suited to humid climates. It performs best in areas with dry summers and well drained soils. A sunny position will produce the best flowering but some shade is tolerated. It will withstand light to moderate frosts. I.trilobus is usually propagated from seed which germinates readily without pretreatment.
Cuttings are also successful using firm, current season's growth.
Some limited work has been carried out by enthusiasts on the grafting of western species of Isopogon onto eastern rootstocks to extend the range where the plants can be grown. It is not known whether I.trilobus has been involved in this work but experiments using I.anethifolius or I.dawsonii as rootstocks may be worth pursuing. You may have reached this description from one of several different sources.