Introducer (below) says 25 ft. (Other than that you should realize that in general tree size development varies with site conditions and other factors - including age of specimen. Somebody that says 15 ft. may not be talking about as old of an example as one who says 25 ft.).

Crapemyrtle Quick Guide Chart

http://www.usna.usda.gov/PhotoGallery/CrapemyrtleGallery/CrapeTable.html

Thanks Rhizo, I'll follow up with the local garden centers that I frequent and see if I can be the squeaky wheel.

Thanks Embothrium, does mature height/width then mean its full size under ideal conditions? Or, does "mature" mean the plants height/width at their 10 year point?

You have to read what each reference is referring to specifically when heights are stated Just as the same kind of tree does not reach the same height on every site not every reference is referring to the same time frame when stating heights - "mature" or otherwise. If no exact definitions are given anywhere in the discussion then the reader is left to assume.

The Myth of Uniform Plant Performance

https://s3.wp.wsu.edu/uploads/sites/403/2015/03/tree-heights.pdf

If 'Miami' doesn't seem to be on the general market then maybe there is another that can be used in its place.

I see this one in nurseries often here in Texas. But to be fair nurseries have a large selection of varieties because they are very popular here and grow really well. I was just at a city park and saw lots crapes mixed in with native plants. I agree with the comment above the same plant will look different in different places and climates but 'Miami' is one of the full size types - a smallish tree not a shrub 25 feet sounds fair. The foliage is larger than many of the other types

Thanks embothirium, the linked article was interesting. The engineer in me wishes there was a way to get a more accurate and (somewhat) tailored growth estimate for a given species but I think the bottom line is that there are way too many variables/unknowns at play.

Thanks Todd. I didn't know the foliage on the miami was larger; interesting.

After a bunch of phone calls, I found another nursery (an hour away) that has a few 15 gallon specimens although they subsequently told me they were ~5 feet tall(including the container) which sounds a little small for a 15 gallon. I may call back this weekend to try and get clarification before I drive out there with our CRV.

I had 2 (25/30 foot) Ashe trees in our front yard that died from the Emerald Ashe borer and had to be removed last year. I don't want to put the crapes in the same exact spots but I'll use them to fill in some of the open space (void). I'm struggling a little with where in our front yard I should plant them. There are definitely places I don't want to plant them due to: (a) county/utility easements (not too close to the road or power lines), (b) existing trees/plants that require spacing, (c) views/sight-lines from inside the house that we don't want to obstruct, and similarly (d) views from the street we don't want to obstruct. It's these latter two considerations and imagining how the (mature) trees would look if they were planted at one location versus another that I find challenging.

Maybe get planning help from a local consultant or designer.

Plants aren't just stamped out in a factory at a uniform size. I would expect such a plant to reach 30-40 feet in height eventually. Just keep it away from power lines and structures, and you should be fine.

I know this is an old thread, but I do have a Miami crape in my front yard. I'm in Forest Hill, MD. It does die back when we have colder winters, especially when we get those late-winter cold snaps. In Annapolis, you will probably have slightly better luck - I can tell I'm right on the edge of it's range to live as a tree form reliably. If you don't mind an 8' shrub that has a few major canes die back each winter, it does have some very stunning flowers. I have yet to witness the exfoliating bark - I had hoped it would grow to it's advertised size of 20+ feet, but that will definitely not happen in northern MD, it would require a zone 8 to do that, I think.