Sudden death for Ornamental Plum?

I have an ornamental Plum tree I planted several years ago. It was doing quite well, and two seasons ago I put a perennial bed around it. Then suddenly it seems to have died - within a matter of 2-3 weeks the leaves all wilted and a windstorm the other day blew them all off. I hope that it grows another set of leaves, but it's not looking good right now - I am afraid it has died.

There does not seem to be any bark damage, and my perennials are all doing fine so I don't think it is a water or accidental herbicide issue. Does anyone have any idea what could have caused it? I am distraught! I bought that tree right after I moved in at a frost sale and nursed it back to health before I planted it, and it was doing so well. Losing one of the first trees I ever planted is just killing me.

They tend to be short-lived, so don't worry about it. Most likely some sort of root disease that performed the coup-de-grace.

Resin

Wouldn't even a short-lived tree usually last more than several years though? I guess it depends on how many "several" was--if it was 4-5 years then it seems like the tree should have lasted a bit longer, but if it was 10+ then that's probably it.

When you put the perennial bed around it, did you add soil, or did you leave the soil level where it was? I don't know about plums, but many trees don't like to have soil added over top of their root zones, this will slowly kill some trees although you may not realize you're killing it until it dies. And does that area get watered more frequently now than it did before the perennials were put in? Even if the amount of water isn't technically overwatering where the plant constantly has wet feet, having more moisture around creates a breeding ground for the fungi in the soil so it increases the chances of some sort of fungal infection that could kill the tree. Even if you haven't changed the amt of watering since you added the perennials, if you were giving it more water than was really necessary all along the same thing could happen.

I put in the perennial bed into the existing soil - this was its third season, and the tree was only in a year, maybe two at the most, before that. I had one of those plastic mulch rings filled with bark around it prior to planting and left it there when I put in the perennials specifically so I wouldn't change the soil level accidentally. I did add a few amendments but I tried to be careful. Everyone was coexisting quite nicely. It is true that that area did receive more water thereafter, but I have extremely sandy soil so chances of it having wet feet or being overwatered are at least considerably reduced. It was very hot that week, and my other plants showed a bit of wilt, but they all made it. I have both plants that love water and some that are pretty drought tolerant in the bed, and so I would think that if it were too much or not enough water one group or the other of those would have died as well.

It was just so sudden. It was growing and getting bigger this year like every other, then it just seemed to crash. I lose small plants here and there, but I have never lost a good size tree! I am heartbroken.

One possibility is verticillium wilt. It is usually not as dramatic as this, but the symptoms fit otherwise. Cut a branch and look for dark streaking under the bark. If it is verticillum you wont want to replant anything that is susceptible. The fungus persists in the soil indefinitely.
Its a shame, whatever it turns out to be. Hope you pin it down so future plantings wont suffer the same fate.

I'm also guessing it was something along those lines, if not verticillium wilt then some other sort of soil-born disease. Plants in this family are also susceptible to Phytophthora which could have similar symptoms and also will persist in the soil, so make sure anything that you replant in that area is not susceptible.