I have white chinese peony and lily of the valley growing in my garden (from my mothers) and I have tried 3/4 times to clear lily of the valley but it is still there in abundance, I took 2 carrier bags full to work and they all took some home! Not a lot you can do regards flowers in bloom at the moment because they are mainly bulbs that were put in months ago, but grape hyacinths bloom this time of year and they do not need any attention, and multiply like mad! Just plant them and forget them forever and each year up they pop. Sweet peas are lovely but the slugs like mine too much so I plant into empty plastic bottles (with tops cut off) and when ground is ready just cut off bottom of bottle and hey presto into ground, no interference with roots. Good Luck.