Q: I recently saw a beautiful tree with purple flowers, similar in color to a lilac, but it is not a lilac. Any idea what this might be? Is it hard to plant and grow?

A: You pose a difficult question to answer without a bit more information. I'll base my response on the following (hopefully correct) presumptions: the tree you saw was in northeast Ohio, the time you saw it was in August or September, and that although the flower was similar in color to a lilac's it wasn't necessarily shaped like a lilac's flower.

My first suggestion is to ask the plant's owners if they know what it is, and if not, ask if you can take a clipping to a nursery or garden center and match it up. A good photograph or two of the plant is very helpful, too, as it shows its growth habit and structure. Actually, good photographs of the flower, and the whole plant, may suffice in its identification.

I'm going to take a wild guess (stressing the word "wild") that the plant you saw was a tree-form hydrangea. If it actually is, it's an attractive plant that is fairly easy to install. It has long-lasting flowers that usually arrive in mid to late summer, when most other plants are long done (flowering-wise).

The flowers can be flat clusters (lacecap), large globes (probably the most common), or tall upright panicles (which is what the lilac flower's shape is). The flower colors that are typically available are red, white, and blue (sounds like you can make an American Flag planting with these first 3!), plus pink, deep pink, and purple.

So, tree-form hydrangea is my best guess. I still suggest getting a cutting (with permission!!), and/or the photograph(s), to have it identified. Please let me know how close I came (or not!).