The taxonomical name "Feijoa" was depreciated in the middle of the last century but since it is also the common name for the plant in both south America and the Philippines, the label is still in use. The correct taxonomy is
Acca sellowiana.
Like many fruiting plants in South America, it is a member of the Myrteae tribe; i.e., it is a fruiting Myrtle. Grafting can be difficult with members of this plant family. However, air-layering works very well with some including Acca, and so does rooting under mist. In general, asexual propagation is easier with the guavas and most difficult with Jaboticaba.
The pineapple guava is native to highlands of Argentina, Brazil, and Uruguay. It is reportedly hardy to 5 F (-15 C), and I can attest to the plants doing just fine for decades alongside (former) apple orchards in Oak Glen CA with winter night-time temperatures in the teens.
The Nazemetz cultivar will produce a full crop of kiwi-size fruit if watered regularly (once per week in my location) and fed equal parts of nitrogen and potash. Be careful though of nutrients that also have significant phosphate. So for example, a "triple 15" (15-15-15) or "triple-20" is not a great choice, but formulas like 18-6-18, or 20-10-20 provide excellent yield. Try to keep the soil pH in the range 6.0 to 6.5.