Out of all the trees I've bought and grown, I regret planting my hawthorn tree the most. It is a bug magnet - had pear slugs for the first few years and now gets cedar apple rust every summer. It looks good when it's blooming but that doesn't last long. The thorns will attack you, and the tree suckers like crazy. I think the suckering might be a sign of distress, but it's very annoying having them sprout all over my flower bed. Yanking them out at the base (rather than cutting) doesn't seem to be helping.
Are there any other trees that should be on my do-not-grow list? (bear in mind I live in zone 2b)