|Flowers of pineapple guava|
A. It’s not clear if you are using these shrubs for their fruit or as an ornamental for its flowers. If you are harvesting fruit, then prune just after harvesting the fruit. If you are pruning it as an ornamental, prune after it flowers.
Don’t use a hedge shears. Instead, remove about one fourth of its entire canopy by reaching deep inside the shrub and cutting a stem with hand pruners just above a side branch. Perhaps 3 or 4 cuts like this is all that is necessary. Your cuts should be hidden, not easily seen, and removal of a stem should not leave a huge, gaping hole.
This type of pruning opens the shrub to sunlight, reduces its density, and causes more growth to occur throughout the canopy. It is done every 2 to 3 years and cleanup is quick and simple. Besides, it is the proper way to prune shrubs of this type.
Cutting only on the perimeter of the canopy with a hedge shears causes the shrub to become dense, boxy and not open to sunlight. This dense shading suppresses growth on the inside and, instead, stimulates growth only on the perimeter. The inside of the plant becomes leafless and woody.