The blessing שהחיינו is recited over fruit that has come into season.
The custom is to recite the blessing when eating it for the first time. But
if a person recites the blessing when seeing the fruit for the first time, he
has fulfilled his obligation.
Lechatchila one should not separate the blessing recited before eating
a fruit from the act of eating. Therefore, the שהחיינו -blessing should be recited
either before making the blessing over the fruit or after reciting the blessing
and tasting it. Nevertheless, if the שהחיינו blessing is recited between the
blessing and the act of eating it, we do not say that it separates the blessing
from the act of eating. Many are accustomed to reciting the שהחיינו blessing
in this way.
If a person forgets to recite the שהחיינו blessing when he first ate a new
fruit, he may not recite the blessing when he eats it later. But if a person
ate a small amount of a fruit, he can still recite the שהחיינו blessing.
If a person is in doubt as to whether he had already recited theשהחיינו
blessing, he should not say it.
A person can recite theשהחיינו blessing over a new fruit even if he
has been eating the same fruit canned all year because other ingredients have
been added to the canned fruit, so the taste of the new fruit is different.