If you cut it down every year once you start it will only grow as tall as it is growing each year. I have found propagations of this cultivar sold here rather low in vigor and wonder therefore how suitable it would be for hard pruning. I have also noticed that when you cut a smokebush down the non-branching replacement shoots snake around unpleasantly, the natural bushy (and flowering) habit being significantly more appealing.

How large it will get depends on where you establish the permanent woody framework. I have a 10 y.o. Continus 'Royal Purple' that I coppice annually to approximately chest high. This produces an abundance of straight shoots that extend around another 3-4 feet and depending on the season, sometimes longer. In effect, the plant pretty much doubles in size during the course of the season and the appearance is that of a evenly rounded, largish shrub densely clothed in large, very deeply purple foliage. Mine is planted directly in front of the golden leafed Robinia 'Frisia' and the contrast is pretty stunning in midseason. You could take it back further but I prefer something with a permanent framework rather than cutting back to the ground or nearly so. As to vigor, I've not noticed any problems with this plant and it responds well to this practice, as does another handled in exactly the same manner at a local nursery.

I believe I'd wait a couple of seasons before I started coppicing routinely to allow the shrub to establish well and develop some girth. If you intend to take it back quite low, you could probably start this process early next spring just as you see buds starting to form on the branches.

Seedlings, of course, have been and continue to be listed both as the true cultivar and also as seedlings of it - so the first question when comparing the vigor of various specimens is are they all really the same clone. I imagine the leisurely growth of true-to-type plants I have encountered on the local market may have to do with them being vegetative propagations rather than seedlings.

It is of course also hoped and assumed that such specimens will pick up the pace after becoming well established. However, the last one of these I planted - in a hot sunny nook on a presumably highly suitable gravelly soil - to form a color relationships with both a long-established rock rose and a long-vigorous Franchet cotoneaster - never developed any significant size before being destroyed by dogs.

Thank you so much for the excellent information. I will wait a few years and see how it does in the spot I have in mind before I begin coppicing. I've been admiring the cotinus coggygria in the rose garden of the arboretum near my home for the last couple of years. They are stunning with the roses and they seem to keep them at about 3 feet. I'm not positive of the variety. Maybe I'll check them out soon and see how they handle theirs. And I'll keep in mind that my plant may not be as vigorous.

Thanks again.