The Spanish Gardener by A. J. Cronin

Harrington Brande an US diplomat is dispatched as a consul in San Jorge, a town in  Spain. He is a rigid, cold, arrogant, extremely pride self-righteous and self-centered person who is unable to comprehend the real needs, yearning of others and is possessed by the outmost envy and jealousy especially if his son shows great affection towards others. He thinks himself as of a person who is entitled to more and who is mistreated, misunderstood by his superiors
This type of personality caused his wife to leave the family, Harrington Brande remaining with his son Nicholas whose health is weak. Towards him shows an almost abnormal paternal love. He sees himself as the only one who can have the love of his son.
Though he loves his son fervently he is not able to comprehend what is best for him. When Nicholas befriends with Jose the young Spanish gardener he is afraid of  losing his son‘s love and treats the gardener badly and with hostility. Harrington is so bedazzled of his own “superior” personality that he is unable to see the real nature behind people. He thinks of  his butler Garcia as of  a loyal servant, ha can’t recognize the charlatan with titles in his  doctor and misunderstands the goodwill of his gardener whom he burdens with hard work out of hatred. Rarely you can read about such a misguided, vengeful character and if you read on you will see that he  is on the road to tragedy, but even so he can not fully grasp  his fate's meaning: sees it as a personal martyrdom.  He is like the turkey bird he reads about at the end,  "by nature a peculiar bird - assertive and self-sufficient - yet because of this inordinate vanity, liable to grave discomfitures ..."
I searched if  "The Spanish Gardener" is available online to read freely, but I have found only "Adventures In Two Worlds" and "Hatters Castle" by A. J. Cronin at Internet Archive site.
The Spanish Gardener at Amazon.
My book's cover is subtitled: "The famous novel from which a famous film was made".
You can watch online The Spanish Gardener at youtube. I need to say the film is different and has another ending.