I'd say larger than 18 inches. But it does grow slowly. Would be easy to maintain by pruning - maybe early in Spring.

I took mine out because a) it's deciduous and b) it bloomed so late in the season for me. After I took it out small plants came up from residual roots.

come on beany ...

no plant in the tree... conifer.. shrub world.. stops growing at some magical height ...


left.. untouched for a decade.. i am sure this thing will be well past 18 inches ... it simply wont stop there...

ALWAYS convert to the latin ... as i have often said ... and look at the pics at the link below .. frankly.. i dont see any that are an 18 inch ball of love ... many are much wider ... and one looks huge.. if its the same plant .. you can check that link ...

so then.. it always falls back.. to the gardener pruning plants.. to achieve or maintain the plant at the size required ...

sorry.. no direct with CMs in my MI

ken

https://www.google.com/search?q=Lagerstroemia+%27Pocomoke&source=lnms&tbm=isch&sa=X&ved=0CAcQ_AUoAWoVChMItNrUq4uSxgIVwgqSCh2EtgDT&biw=864&bih=745&dpr=0.9

mine is over 4' tall, maybe 7 years old. never pruned. not a heavy bloomer but perhaps because it needs pruning(?)

I may eventually take it out. they (those dwarf crapes) are just not really good looking plants, to me. all crapes are deciduous in my area.