Logan, you made no actual suggestion for method of application. As I said, salt is not a deterrent. It has to touch the slug to affect it. In a damp climate salt is useless unless sprinkled directly onto the slug. Salt is hygroscopic. It will be diluted and dissipated almost immediately. Even proprietary slug baits have to be reapplied constantly. Btw, I believe that in a container it is more likely to be snails than slugs, since they are great climbers and, having shells, venture further from the shelter of the ground. Regarding the wool, my allotment neighbour tried it and reduced snail damage. Whether that was coincidence or cause I don't know.

Yes, you can get good bloom for a time on older interior twigs of sheared ones - until these older stems wear out. Deutzia are what have been called "cane growers", with comparatively short lived individual stems. Successful management of these shrubs involves periodic removal of spent canes and allowing of new stems to grow to all or most of their natural shape and size, to produce a graceful specimen with an attractive natural shape. As always with plantings of any kinds of shrubs, it is much better to choose kinds that will fit within the space for a reasonable period of time than to spoil them with repeated shearing or other hard pruning intended to force them to stay within bounds.

The dwarf cultivar 'Nikko' has been doing very well in my mixed border for several years, growing in the dappled shade of oaks, with only a few hours of direct sun in the afternoon. It blooms well, foliage remaining attractive throughout the season; it does sometimes take root where branches touch the soil, but not to the point of being a problem ... Easy enough to cut them off and place elsewhere if I wish. Old-fashioned tall fuzzy deutzia is growing in dappled shade (again, tall oaks) in a neighbor's yard all along the fence line. I always loved this shrub, as there was one in our yard when I was a child. However, lately I've noticed volunteers coming up all over my yard. In the 35+ years we've lived here, this is the first time it has happened. You'd think I would be pleased, but they grow so fast, spreading out as well as shooting upward, and reseeding so prolifically, I've been pulling them out of my small yard and will just enjoy the neighbor's shrubs when they bloom.

Hmm - normally I'd agree but these are single leaves sometimes well up the branch and maybe the only one with all other leaves perfect. They're not as you'd expect for oldest (at least to me) the leaves at the base of a branch. However, I'd agree the soil needs changing which is why I did the top dressing as I didn't want to halt the flowering for the year. If it survives until after flowering I'll do a proper repot then. Thanks.