Ageratum? Here is a link that might be useful: Ageratum houstonianum

Your Daisy resembles Tanacetum corymbosum. Here is a link that might be useful: Tanacetum corymbosum

sorry about ma ... listen to me.. you are not asking the right questions .... the issue... is that mom probably used to putter out there with endless hours to make her garden ... let me suggest.. that as you roll thru these ID's ... and presuming you dont have unlimited hours ... that you ask about how vigorous a given plant is ... with this vine.. beyond Id... what i read in the answer given... is that if you arent out there with a machete every 45 minutes.. it MIGHT take over the whole yard... so whether or not mom ... GRHSoul ... thought it was a nice plant.. perhaps you dont want it there... to swallow up and seed all over the garden ... when you have your back turned ... good luck with your legacy garden ... ken ps: your other post... i have no experience with that plant.. but just looking at it.. makes me think the same thing ....

Yes, topping them down to 8 or 9 feet should be fine. To get more density/fullness, adequate water and fertilizer, then tip prune and tip prune and tip prune the new growth to gradually develop more leafy stems. The basic problem is they are planted too close to each other and too close to the fence, so can't develop enough branching and foliage to look really good. Someone was in a hurry to get a screen and didn't think long-term. Good care and patient light trimming over a period of time can make them look a lot better than they look now, though.