My 7 acre lot was completely covered with eleagnus. Mine is
deciduous, has reddish and yellow berries in the fall, and
good-smelling light yellow flowers in the spring. It is horribly
invasive. I have pulled hundred of them. Luckily they grow back
slowly, but this year there is a huge "bumper crop" of them coming
back all over. I have left one batch purposely as a privacy hedge,
and as long as you stay on top of it, it won't become invasive. Mine
had a 60 year start when I got the lot.
Kira