Not all plants are pruned in the same fashion or at the same time of year, so you will need to do some research on the different plants if you don't get enough feedback here. Get a good book on pruning either from the library or buy one (Timber Press has a sale on of 30% off the entire list + free shipping for orders over $50) or do a web search for your plant (ie "spirea") and "pruning". If you opt for the web search, be sure to use good choices for sources of info such as a botanical garden or Fine Gardening magazine's website.

With almost any plant you can start by cutting out dead wood and any branches that are rubbing, though don't prune live material now (in the warm part of fall) since it will encourage the plant to grow new material that won't have time to harden off before it gets cold.

Hydrangea paniculata and H. arborescens can be pruned after it gets cold enough so that there's no chance of pushing out new growth, or next spring early. Both set new flower buds in spring. Some folks prune H. paniculata to control size, but to me that is too much labor, trying to make a plant fit my space rather than choosing a plant of a suitable size. There are H. paniculatas that grow from about 3 1/2 feet and others to 10 or more feet, so you really have a lot of choice. H. macrophylla sets its buds in the fall and so should be pruned right after bloom in the spring in order not to lose the flower buds for the next year.

Spirea can be pruned to the ground and it will resprout. If it's a spring bloomer like bridal wreath, I'd wait until after bloom and then prune out 1/3 down to the base and repeat each year for 3 years. If it's a summer bloomer or you don't care about the flowers, you can prune the entire plant to 4"-6" in early spring before leaves open and within 2-3 weeks it will be growing new stems. I do this when my spirea have been squashed by snow and ice coming off the roof.

For the Rose of Sharon and Weigela, if you prune them, they will regrow to the same large size within 2 years or so. Do you have a spot that will allow them the space they want or do you want to have to prune them on an annual or biennial basis to control size? Again, it sounds to me like more work that I would be wanting to take on.

I can't help on the reblooming lilac or the J. maple because I don't grow either.

Since these shrubs are inherited and it sounds like many weren't planted in appropriate spots (since it sounds like for many branches and bloom are sparse or the plants are too big), feel free to remove any that don't fit your taste and/or aren't healthy. If branching and/or blooms are sparse, check out the sun requirements of the plant to see if it needs more sun. Plants can always be moved or removed entirely, particularly if they weren't your choice in the first place.

Japanese maples never need a lot of pruning!! In fact, pruning these trees should be approached with a very light hand, unless it is the removal of any deadwood, which can always be removed (and should, for the health of the tree). And it is not at all uncommon for the weeping dissectum types to develop skirting branches that sweep the ground, although these can be lifted.

I'd suggest you post photos of your tree in the Maples forum and some of the JM enthusiasts there will provide direction in how to approach any pruning.

My maple looks like Cousin It from the Addams Family! There are so many layers of branches that I can't see the base or the trunk or the bark. There could be a family of skunks living under there and I'd never know! Let me try to find a photo...

Thanks you for all the extremely in-depth and helpful info! Lots to digest and think over :)

Please tell us what you think it should look like?

I think your japanese maple looks beautiful - and probably pretty much what it is supposed to look like! I strongly agree with gardengal that you should post this on the maples forum for suggestions - maybe a tiny bit of pruning on the bottom/lower branches to see the trunk or a bit of the form - but from my limited experience it looks fine. Do you know what kind it is?

I have no idea what kind it is. Neither does the previous owner.

As far as what I think it should look like? Well, I don't think the branches should touch the pavement as I think that's probably not good for them, right? I have read that the branches shouldn't rub against each other and I'm certain that they do. I guess I thought I should be able to *ever* see the trunk or the base of the tree to assess the health of it. But perhaps I'm just totally wrong. The back of the tree is squashed up against the fence and the stairs, so I thought I should probably do something about that?

I have posted in the Maples forum and received 1 response which was sort of helpful, but I have more questions that have been left unanswered. Oh well. In the absence of info, I'll just leave it be.

I'm totally not bothered by it. More that I want to make sure I'm not being neglectful. If the consensus is to leave it be, I can handle that! :)