Are you sure those trees are getting enough water? That sounds like the most likely issue but it could be something else.

Another possibility would be too much fertilizer. Have you fertilized and are these newly planted trees?

Yep, newly planted trees. Both the vigorous and non vigorous trees got a healthy dose or organic fertilizer when they were first planted dormant late last fall. An adjacent nectarine tree is suffering from nitrogen deficiency, so I just re-fertilized everything with a handful each of triple 16. Watering should be sufficient (3 times a week) but I could double down. Everything is planted on a steep south-west facing hill. I also just mulched the hell out of them to see if excess soil temp is the culprit.

Other than the taco puckering, the color is deep green and healthy. I am most concerned with the tip die-off, as it is clearly holding the tree back.

It won't be excess soil temperature at this point in the year. Cool soil and too much water can cause issues such as iron deficiency as well as drowning the roots.

Three waterings a week might be too much especially if the soil drains slowly. One good watering a week should be enough especially with all that mulch and no weeds

What you are identifying as nitrogen deficiency could be caused by too much water. Or if the soil drains really well you are flushing out the nitrogen.

I identified the soil definitely drains well on this slope. The soil is damp-dry within a day of watering. My soil is sandy shale with a shallow hard pan of shale, but with the slope and south facing slope, the water melts away. I will slow it down to once a week.

Thanks. Stay tuned to pictures tonight.

Afflicted aprium

Afflicted apricot

Normal apricot

I'm suspecting salt burn ie too much fertilizer. But at any rate they look like they'll be OK.

Can you apply too much gypsum? I already checked the PH, it's 6.5.

No not gypsum. But that 16-16-16 or similar needs to be used sparingly on newly planted trees. Some organic fertilizers can also be high in salts.

Gotcha,

In that case, i will spread some gypsum to displace the salts, slow down on the watering, and won't feed again this season.

This post was edited by ahajmano on Tue, Mar 26, 13 at 12:27

If your soil drains well, and it probably does, a couple good waterings will leach out the salts. It sounds like you are maybe just trying a little too hard. I'm in the same boat right now trying to start some early outdoors watermelon with three nights in a row at about 25F. I'm so worried about the cold I think I've about killed them with too much heat. Had them well covered the other night and a light bulb underneath. It was 95F under there in the morning after 25F outside.