Higgs Boson wrote:

I have two fruit trees about 3-4 years old. The apricot (Blenheim) is doing fine, but the plum (Santa Rosa) keeps making suckers from the base. I removed these and it looked like the tree was leafing out the same as the apricot, but now more suckers from the base.

Is there a reason that only one of these keeps making suckers? Inquiring minds...

Probably each has a different root stock. Some stone fruit produces
suckers forever. I have two plum trees, both different, but both
produce suckers every year, a few from below the graft and a few from
above the graft... it's just the nature of the beast. Some I catch
early and simply brush them off with my hand, some escape my view,
become more established and require a pruner. My ginkgos produce
suckers all along their trunk constantly. I always considered suckers
an indication of a healthy plant.