Hi Gwen,
to NGA
There are no short cuts to identifying plants. Through study, research and practice, anyone can learn to recognize the characteristics of plants that eventually lead to an ID. I don't know how the rest of the folks here gained their knowledge and ability to find the identities of plants but I don't think any of us has a magic button. If we did, this Forum would quickly become obsolete.
If you have read some of the posts made on this site, you know that there is often a lot of discussion before we agree on an ID and sometimes we never do.
Maybe instead of trying to find an App, you could make it a learning experience for all of you by discussing the characteristics of the plants common to your area. Did you know that roses and strawberries are related? That peaches, cherries and almonds are in the same genus? What does the houseplant you call "Benji" have in common with Fig Newtons?
You get my drift...
Daisy