I hava a climbing hydrangea plant which is unwillingly sharing space with some sort of invasive tall grass. I can't pull it out faster than it grows and can't dig it out - it's interspersed with the hydrangea. Is there anything that would kill the grass but not harm the hydrangea?
Hmm. Has the hydrangea grown taller than the grass? Would it be possible to create some kind of grass-suppressing barrier, through which one or more stems of the hydrangea would be permitted to penetrate? I'm thinking -- as an almost free solution -- of taking several layers of newspaper, poking a hole in the middle, threading the hydrangea through the hole, and laying the newspaper down on top of the grass. You can top this off with a heaping of mulch, or just anchor it with some rocks or bricks or any weighty objects. Water should be able to penetrate the paper, but the grass should not be able to punch its way through. After one year, the grass should be dead and the paper should be rotten.
