They do well under the same conditions as H. macrophylla.
Rich, well drained soil, with some sun exposure.
I have heavy clay, also and a sloping terrain, so few issues regarding drainage.
I grow several of the H. asperae clan; villosa, sargentiana, kawakamii & strigosa. Of that group, strigosa is the most tender and probably would be rated USDA Hardiness Zone 8 (10°F), without protection. All others are Hardy in my Zone 7.
None have obtained heights in excess of 4Ft(1.2M) after many years, but do tend to spread in girth.

The H. asperae subsection is not widely available at local retail nurseries in the US and are usually grown only by collectors.

Thanks for the information, I might try it then. I have no idea how common it is over here, sometimes plant shops sell a few more rare kinds, probably because hydrangeas in general are very popular garden plant here and this particular nursery generally has a good selection of more interesting shrubberies. :)

How should I prune it by the way?

The only pruning I've found to be necessary, is removing dead canes each spring, after the plants are fully leafed out.
If you were to prune them, for appearance or to control height, it should be performed soon after the flowering period, as buds for next season's blooms will be forming in late summer.

Thanks, I will keep it in mind. :)

Various asperas are quite common here in the PNW......but then, this is pretty much hydrangea heaven and ALL species of hydrangea are well-represented. Under proper growing conditions, aspera var. villosa will get to be a very large plant. There is one at a local botanical garden that is 15' tall and nearly as wide.

As to pruning, don't :-) Bloom time is late....much later than macrophyllas (August to September here) so too late to prune after flowering and still expect a decent bloom the following season and really the only encounter mine has ever had with pruners is to deadhead to 'tidy' up the plant in spring. In my zone 8b climate, there is very little dead wood ever produced by this plant.

Bear in mind that I am in Tasmania, mine are flowering now and look wonderful. Advice please on propagation, as everyone admires them and I would like to be able to share them

The information that I have suggests taking cuttings in late summer. You can also propagate by seed but they would not be true to the parent.

H. aspera Sargentiana produces suckers but I have yet to read whether Villosa also does. Should I assume it does not based on your question about your villosa?