Do you mean vegetable gardening?

sandk, Thank you for the suggestion.

rhizo, She‘s looking to understand annuals, shrubs, perennials, not fruit or vegetable gardening.

I second the BHG book. I have given it to several novices. I find it very helpful myself, and I've been gardening for decades. One of the things that I like about it is that it doesn't recommend just "usual" plants and sprays, but covers native plants and organic treatments. It is a really good book for gardeners.

It's got an unfortunate title but Gardening Basics for Dummies (or any in the Gardening for Dummies series) offer easily understood and accurate suggestions/methods. Easily found on Amazon and often used copies for a minimal expense.

Thank you all so much! I’m sending them to her now.