And your Walden Pond-type experience is partially based on a non-native plant as well.

"In the 17th century, English settlers brought the apricot to the English colonies in the New World. Most of modern American production of apricots comes from the seedlings carried to the west coast by Spanish missionaries."

Your Russian olive trees are no more 'invasisve' or less 'invasive' than the apricots you recall so fondly.