Feijoas are a really hardy fruit tree. They can handle dry coastal conditions (once established) right thru to damp winter clay. They do grow best in full sun but will grow quite happily in half-day shade as well. They grow reasonably quickly into a good-sized shrub/small tree at around 4M tall, and 3M wide. Or they can be kept smaller with regular pruning or trimmed into a hedge.
All varieties (apart from Unique) fruit much better when planted with another variety to pollinate them. And as the varieties all ripen at slightly different times, you could buy one of each and get a long feijoa fruit season rather than a glut all at once.
Varieties generally available are:
Unique
One of the earliest ripening varieties, Feb/March. Very sweet and juicy, medium- sized fruit. Self-fertile.
Gemini
Has a smaller, smooth-skinned dark green oval fruit with a highly-flavoured flesh. The flesh is a little gritty. Is self-fertile but will crop better with another variety nearby. Ripens in March.
Mammoth
Large round to oval fruit, with gritty flesh but a great flavour. Is self-fertile but will have larger fruit if pollinated with another variety nearby, such as Triumph. Ripens in March/April.
Apollo
A vigorous growing variety with large, aromatic rough-skinned very sweet fruit. Partially self-fertile but pollination with a different variety is essential for large fruit. Ripens in March.
Triumph
Medium to large-sized fruit. Flesh is slightly gritty but with good seed to pulp ratio. Lovely sharp flavour. Bears heavily if pollinated with another variety, such as Mammoth. Ripens in April
Bret's Delight
An improved selection forming a compact, medium-sized tree. A true heavy cropper with delicious, large, thin skinned fruit. Smaller growing at just 1.8 x 1.2m
Sellowiana
This is a seed-grown Feijoa which is great for hedging. No guarantee of what type of fruit you may get, may be small, may be good-sized, may crop heavily or not at all. Any fruit is an added bonus when these are used principally as a hedge.