What kind of trees are these?
Welcome to Minnesota!
It's a little hard to tell from your photos if these are trees or shrubs. It seems that they are growing up close to a structure - and therefore they are probably volunteer plants (not planted purposefully by the previous owner).
The pink/yellow fruits may be a variety of plum.It seems that the plant has serrated leaves, but it's hard to tell from the photo how large these fruits are. Even here in the northland, plums tend to be at least the size of a walnut, so if you can tell us how large they are it might help.
The plant with the blue/black berries is probably one of our most problematic invasive plants - the Buckthorn - see if this description matches what your plants are exhibiting:
These berries are poisonous. Their seeds persist in the soil for a number of years, so if you choose to remove these bushes, be aware that you may find new plants coming up in the future. They are easy to remove when they are seedlings.
I hope this is helpful. Please contact AaE again if you have further questions.
Thank you. I think you are right about the buckthorn. It is definitely not something that was planted. I am finding the owners before us just let anything grow so I have quite a few weed trees to deal with. The plum tree was intentionally planted, though. I'm thinking it must be some native tree because I saw one in Chaska along the lake bank by the courthouse last week. They have thorns on the branches if that helps. The fruit are about the size of cherries so it probably is the cherry plum. They start out green then go from yellowish orange to pink to purple, but a lot of them shrivel up before they get completely purple. (I read online that that the shriveling up is caused by some fungus. )I'm assuming it is beautiful in the spring and that is why they planted it because the fruits to me are not edible and they make an aweful mess on the ground that attracts wasps. I'm trying to decide if it is worth keeping or if I should cut it down and plant something else. Is there anything that can be done with these fruits other than clean them up and if so, do you know what I can put on them to get rid of the fungus.
Well, wild plums are definitely labor intensive if you want to eat them. In my opinion, they make the very best jam! You can find lots of recipes on the net, but because they are so small you would need a full tree's worth to make it worth your time.
They are very susceptible to Black knot, and other fungal diseases:
And as I recall from my childhood - hornets and wasps are always first there to get the harvest .
If you aren't wild about this tree I think it would be a good idea to replace it with something less troublesome.