Question
Hi Nick?br> I am asking this on behalf of some friends here in Durham, NC.  Elevation 350ft, Their properiy's native soil is a sandy clay type.

CIRCUMSTANCES:
They recently planted two Pineapple Mango trees, about 3 ft tall, 5 ft apart, in a protected location which gets morning to early afternoon sun.   After that, they trees are shaded by the garage.   New growth is plentiful and healthy, no yellowing or other spots on the leaves, no insects or residue on the underside.   They did not loosen up the rootball before planting, but did amend the soil thorough going out a foot from where planted.  I thought the trees looked a little too deeply planted for good drainage, so I suggested lifting, cutting and teasing out the roots, then replanting 2 inches higher.

THE QUESTION:
1)  Many of the mature leaves have dried on the tips and edges closest to the tips.  I understand a photo is helpful, but I do hope my description is enough.  They have two of these and are looking forward to protecting them through the winter so they grown into fruit-bearing trees.
2)  For overwintering, I suggested using stakes taller than the trees, away from all leaves, and then wrapping it in clear plastic sheeting to protect from wind and conserve moisture.  I also suggested piling on the straw as many do with fig trees in colder climates.   Is that a good wintering treatment?

Thanks!

Answer
Jona,,,you were wise to notice they may be planted to deep,,,,they should be exactly at the level they were in the nursery container; another mistake is augmenting the soil,, they should be planted in the native soil, regardless of how good or bad it is, for they will do fine until the roots hit the perimeter of the augmented soil then the roots will take the path of least resistance and begin a circular growth pattern, which will eventually lead to a root ball that is weak and unnatural thereby compromising the crown eventually. The root ball should have indeed been spread and loosened (another good observation on your part). All this is a good starting point, but I live in Southwest Florida and in my 9a climate zone , I would be hard pressed to attempt to grow them because of their severe sensitivity to cold,,,never mind freezing weather! Your preventative measures are well thaught out, but I fear that even they would not save them if the temps drop down in the low 20's...a better idea would be to plant them in large containers and be able to move them into a garage during cold spells, then move them back out when the daytime temps go back up. I encourage this for colder weather areas when People desire to grow a tropical plant. The browning tips sound like a lack of humidity , but it could also be a struggling root ball. Nick