April 1 would be a good time to to prune them back as far as you want.

The best time to prune a buddleia is right now and to the ground! And with a shovel :-) It is listed as a noxious weed in both Oregon and Washington and is on the 'watch list' of various other states.

Panicle hydrangeas bloom on growth produced the same season ('new wood'), so pruning can be done in late winter or early spring before new growth begins.

Yes: Like other summer bloomers both are cut back early in the year. The butterfly bush starts into growth well before April, so that would be late. Each time you do it you prune a little farther out than the previous year. Study the growths and cut with more than one set of overwintering buds left from last season. Look at some illustrated pruning books to see what to do. Do not keep cutting back to the same point each time.

The pestiferous one is B. davidii. I have also had one of its presumed hybrids (a local selection raised from seed of B. fallowiana but having B. davidii characteristics and resembling other such introductions) seed into a parking area near the original planting. Other kinds (BB. japonica, globosa etc.) being grown in this region have not shown this same propensity.

No kidding... let's not demonize all Buddlejas just because one of them (and its hybrids) is bad. Same for Euphorbia, Cytisus, Tamarix, Rubus, and maybe even Hedera.

It is pretty safe to assume when someone here mentions a Buddleia/butterfly bush they are talking about B. davidii. To an extent it's like that's all there is, the others being much less prevalent.

So, if I prune these two in October I would be screwing them up?
Yes, I did ask, but wondering what would happen if I pruned back the hydrangea in late October since the new growth (all of a sudden, after 4 years) is shooting up and blocking my front window.

October is not an ideal time for pruning woody plants. Pruning stimulates growth and often PNW autumns - even into October - are mild enough for plants to push new growth, especially since roots are very active at that time of year. New growth produced at that time of year is more susceptible to winter cold damage so you run the risk of creating problems for the plants if you prune that late in the season.

A better plan is to wait until late winter or early spring and prune then, just before or as new growth begins. And you might want to consider relocating the hydrangea at that time as well if it is growing too large for its current location.

Thanks, I will tough it out and prune them late winter. The hydrangea was fine for four years LOL and must've just gotten "happy" ;-) and sent out all these tall spires!