My Mom had a Eucalyptus that looked a lot like yours, in Bellingham. It would grow up, but never with a single straight trunk, then every several years a cold winter would kill the top, and it would then resprout from the roots. This meant it never took over. I suspect you could therefore cut it back every few years, so it would grow as a shrub. Hers always looked rather straggly, and did not cast much shade. She really liked it because she could cut branches for flower arranging.
