If you have a large, invasive tree...the lowest effort way to kill it is to pry the bark off in a complete circle around the base of the trunk to girdle it ASAP. Here's how to do it on Glossy Privet, but the basic technique can be applied on any tree. And a shovel will work too to pry the bark off. The reason why it works is that it prevents the photosynthesized sugars from going down to feed the roots...which then slowly starves the tree. This works on various types of trees. I've tried it myself successfully on Glossy Privet and Chinaberry already. Typically, the existing branches will stop leafing out and it will resprout from below the girdle over the next half year. Obviously, break any of those resprouts off, and keep starving the roots. And then watch the tree continue to die off after that. The great thing about this method is that it requires no toxic herbicides and little manual labor, too. Now once the tree dies for good, you can just let it rot in place for a while before cutting it down in parts at your convenience to prevent falling hazards. Of course, if the tree is a sapling or smaller and can simply be uprooted, then that's even easier and faster. And if it's multi-trunked and srhrubby, then girdling gets a lot harder. But for large, single-trunked trees...IMO, this method is the best option.

Just remember Halina it is a big tree they can grow 50-70ft it could have a 45ft tap root. I would not even plant a tree that grew that tall so close to the house I am on 3/4 acre and I dont think this block is big enough for a tree that tall. The Powton is a specially bred and select form of Paulownia kawakami (Paulownia) a native of China. They do not like their feet wet so resent over watering... I know it has a very pretty flower, best to ring up the nursery where you bought it from and ask advice there..Have a look at the link below lots of info there... Cheers..MM. Here is a link that might be useful: Paulownia Trees

We really do need to see photos to determine what is going on, otherwise we are just guessing and you then may be following advice that is not appropriate or could even prove harmful. FWIW, horticultural oil is NOT a suggested treatment for borers.......if that is what you have. Because the larvae tunnels (bores) into the wood of the tree, any sort of topical approach has to be carefully considered and timed to have any effect. The bugs are not inside the bark....they are inside the tree and it often requires a systemic (seldom recommended for edibles) to ensure effective control. And the appearance of sap - aka gummosis - can arise from a multitude of conditions, not all of them serious or requiring treatment. Photos, please!!

not many things die just from cutting back .. as noted by all the prior cut backs on that tree ... cut down.. and apply any stump killer ... undiluted.. per label ... painted on as noted above ... and while you are at it.. i would probably kill the shrub behind ... and replant sone quality plants 3 to 5 feet away rome sent legions to salt carthage .... you dont need that many men.. if you use the right product ... lol ... ken https://duckduckgo.com/?q=stump+killer&t=ffcm&ia=products