In some areas St. John's Wort may
be invasive. We have not seen that here. In fact, with our dry hot summers
and multitudes of gophers, we have trouble keeping it alive which is a shame
because it makes a great beneficial
Large quantities ingested by livestock or
horses is poisonous.
The patch below
has been there for over 15 years because our climate is very dry it takes it
a very long time to spread. This section is about four feet by three feet.
It is on a drip which also keeps it from reaching further.