折腾 is a relentless act performed on a certain thing or matter, that may cause unnecessary problems or get results that go against do-nothing. The act is deemed compulsive and somewhat excessive from the view of normal behaviors.
沒事找事瞎折腾啥呢?！= 沒事找事瞎忙什麼呢?！(Why busy at that stuff/thing which is nothing to worry about).
折腾夠了嗎? 消停一下吧! 忙/做夠了嗎? 消停一下吧! (Isn't the disturbing/fruitless action enough? Please stop).
不要再折腾了.那只會愈搞愈糟糕的! = 不要再忙/做了.那只會愈搞愈糟糕的! (Stop the disturbing/fruitless active, which merely worsen the situation).
Similarly, the sentence,
"....开始折腾各种盆栽" = "....开始忙着種植各种盆栽" (start to busy at poting/planting all kind of bonsais).
and, the following sentence "在公寓里折腾了盆栽还不够，..." implies after the act of "开始折腾各种盆栽", this suddenly-turned-flower-lover is unsatisfied with the number of bonsais had planted, which is deemed plentiful by the writer. The "折腾" here, therefore, is echoing, or an emphasis of, the 折腾 in the previous sentence.
I think the translation should take the full context into consideration rather than word by word, so my translation is:
"以前有段时间，他很喜欢养花，开始折腾各种盆栽。在公寓里折腾了盆栽还不够，他還/甚至..." - At one occasion/time, he suddenly falls in love with flowering and started to busy (折腾) at planting all kind of bonsais in his apartment. Yet, wasn't satisfied/feel enough with the potted plants at home (the 折腾), he even/yet....