You don't want to use most herbicides around the pond, however you can use a hand sprayer and a herbicide that works on the bark. Its still a lot of work spraying each bush but it beats clearing by hand. I used Garlon 4, its expensive but it works and you can apply it in late winter when it easier to get to the brush.
Advantages
Effective year-round for selective control of trees and brush.
Can be applied at any time of year, including the winter
months, except when snow or water prevent spraying at the
desired height above ground level.
Year-round usage allows efficiency in crew allocation and
supervision.
Can be used where foliar applications arenât convenient, such
as on steep or uneven terrain.
Applications are targeted, greatly reducing the potential for
injury to off-target vegetation.
Minimized impact on environmentally sensitive or erosion
prone areas.
How basal bark treatments work
Young bark is lipophilic, meaning its structure acts like an open
lattice, and allows fatty substances to move readily within it.
That is why Release or Garlon 4 mixed with an oil carrier is
able to move within and through young bark tissue. Basal bark
treatments work best on young tender bark.
This inward movement reaches and penetrates the cambium
(conductive tissue) and results in the herbicide creating a
chemical girdle of the stem. Complete control depends on the
stem being entirely encircled â termed âwrap.â Once the
chemical girdle is formed, it acts like a physical girdle to prevent
downward movement of nutrients to the roots, thus eventually
killing the treated plant.