How close to a house can a single-trunk adonidia palm be planted
To replace palm that died from fusarium
Certified GKH Gardening Expert
Five or six feet to allow a somewhat full foliar spread, but maybe you can get away with closer if you can accept a one-sided canopy. The trunks don't get that big, nor are the roots very invasive, so you can go closer than with other palms. But I would say three feet at least.
Are you sure that it was fusarium wilt that killed the previous palm, and not lethal yellowing or gandoderma root rot, which could affect your new palm? Christmas palm normally is not susceptible to fusarium, but I would do a soil drench before planting with a biological fungicide to suppress soil borne diseases.