The Prince's charity helps children who have suffered loss as well as poverty.
The gardener said: "One thing that's important in life is shelter and a home. Harry is someone who has lost those parental arms that we all need round us. He knows all about it, of course, that kids deserve to be loved and picked up."
Asked whether the garden represented a memorial to the Prince's mother, she said: "Absolutely. I feel the spirit of his mother in this garden, which has private areas as well as public parts.
"The charity was set up in memory of his mother and is very much in the spirit of her. It's the kind of thing she would have done and I'm sure it would have made her proud."
Blom admitted that she thought twice before agreeing to create the garden when she was approached last August.
"I wasn't sure about it. It's so exhausting doing a garden for Chelsea," she said, but after visiting Lesotho to see the landscape and experience the work of the charity there she "was aware of what I wanted to represent".
She said that the Prince had seen all the plans and was being kept informed at every stage, adding: "He's very enthusiastic. He's very involved and, so far, has been very happy about everything I'm doing...He is very excited about it. He trusts me. But, at the end of the day, he's a soldier not a gardener."
The famous annual Chelsea Flower Show runs from May 21-25 at London's Royal Hospital, and it's been reported that Prince Harry's involvement this year has boosted ticket sales.
Blom, who trained as a psychologist specialising in mental health issues before changing her career, designed a Chelsea Flower Show garden in 2002 for the Prince of Wales and told the magazine: "He told me I'd be damned if I didn't and damned if I did!"
The landscape gardener, who has planted 12,500 plants so that 4,500 are up to scratch, fears people won't "get it" when they see her new creation, adding: "I'm not sure if this is what the Royal Horticultural Society is expecting! But, there you go."
She added: "I know what people think of Africa. They assume it's all dry and hot and full of lions and giraffes. But Lesotho is wet and cold! I have reflected that in the garden. There's not any dry grass or African animals in sight."
- PAA