Oh, Ruby, I've been gardening for years and truly live for it, but with that said, there are many times where someone is looking to identify a species of plant, shrub, or tree, and I still scratch my head as to what it might be.
Gardening today has moved so far beyond that of the past, where a typical flower gardener arranged their soil-beds with well-known and popular varieties of traditional plantings, unlike today where hybrid varieties and other more exotic species can be found more readily.
Like most anything and everything, the more you work with, and are around gardening and plantings, the more you begin to naturally recognize what it is you're looking at. Experience is everything when it comes to gardening, and there's no better teacher than getting ones hands dirty.