flush or not to flush

ok i know antifreeze is bad for critters
but what about plants?

just moved into a new place (for me that is)

there are no storm drains just flows off the driveway onto the weeds.
would like to have some "good" plants grow there
would this kill the dirt or wash away down the hill?
wait till winter rains to dilute it big time or ok in the summer heat?

no way to collect or contain the drain from the system let alone a place to take the used stuff to.
can run gallons if water to wash it down hill (on and in dirt). paved roads but no curbs or gutters.
city water (in and out) no wells within a couple miles that i know of.
but city water is well water. have a lake with in three miles but east-bay mud owns it.

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