Answer: With a new plant, I would expect it to reach about four feet this year after a hard winter pruning as a guesstimate.
At maturity, this is a large shrub and can reach the size you were expecting. If you cut it back very hard every winter, it will need to regenerate each year and this will limit its size each season at least in the early years. As the plant matures and the root system increases, it will regrow faster each season and consequently also be able to increase its overall size from year to year, but you will have that waiting period each summer between the cutting and the months until it gets big again.
The trimming stimulates new twig growth and thus enhances coloration since it is best in new twigs. If you need a large plant in that location, try trimming just a portion of the stems back each winter. By removing say a third of the plant each year (cut some of the oldest stems off short) you will always have some colorful newer stems and retain the bulk of the plant at the same time.
If the coloring is not important to you, allow the shrub to grow and just thin it every few years to remove crowded growth (cut out a few of the oldest stems at the base) and of course, routinely remove any dead or diseased wood.
I hope this helps you decide what to do.
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