What caused my meiwa died?

[dragon]

All the branch of my meiwa kumquat gradually turned black and died . I trimed all the branch, and pulled it out the old pot. What caused the branches died back? I only have the rootstock left. Do you think it will survive to be grafted on later.

[Millet]

Is this tree in the ground or in a container?

[dragon]

Is this tree in the ground or in a container?

It is in container. I have several kumquat trees in containers, but only it died on me

[Viking Guy]

Got a pic of pot and rootstock?

[JJROSS54]

My experience with this has been the roots are staying to wet either due to over watering or the soil has become compacted or to dense to allow enough oxygen to the roots, I have heard this called twig die back and have had it happen a couple of times, once on an in ground tree I was over watering and another in a pot with the wrong type of potting soil that stayed to wet and caused root rot. The graft died but the root stock is surviving, I will see if it comes back on this springs flush.

[brian]

Did the leaves drop off first?  Or did the branches die with them still attached?

When I've had trees die of wet roots the leaves yellowed and dropped first.   When I've had trees die of thirst the leaves dried out in place and stayed attached

[Millet]

The problem that has caused your tree's die back and leaf drop it certainly inside the container.   What has happened to your tree is rather common.  You need to pull your tree from the container and examine the roots. Soft/mushy dark brown roots are dead,  and with very little pull the exterior of the root will pull away from the interior core. Live roots are a light tan color and could  have white root tips if the roots are actively growing/expanding.    Examine your roots and let us know what your find. A close picture would be extremely helpful.  My guess on the cause your your tree's death is much the same as JJROSS54's as written above.

[dragon]

Did the leaves drop off first?  Or did the branches die with them still attached?

When I've had trees die of wet roots the leaves yellowed and dropped first.   When I've had trees die of thirst the leaves dried out in place and stayed attached

Yes, the leaves dropped first, then the twig gradually turned black and dried.

The problem that has has caused your tree's die back and leaf drop it certainly inside the container.   What has happened to your tree is rather common.  You need to pull your tree from the container and examine the roots. Soft/mushy dark brown roots are dead,  and with very little pull the exterior of the root will pull away from the interior core. Live roots are a light tan color and could  have white root tips if the roots are actively growing/expanding.    Examine your roots and let us know what your find. A close picture would be extremely helpful.  My guess on the cause your your tree's death is much the same as JJROSS54's as written above.

When I pulled the tree out, the roots had white root, not black. Sorry I don't have picture to show you because I already put it into another pot. I used a lot of coconut coir mixed with potting soils. Hopefully, the rootstock is not going to die

[Millet]

A mix of Coconut Coir and potting soil is not a very good medium for citrus.  5 parts bark chips, 1 part  peat (or coir) and 1 part coarse sand, or  Miracle Grow Garden Soil (MGGS), but only If your location offers the MGGS formula that has extensive wood chips as part of the product.  In some location of the country MGGS is formulated without the bark chips.  The above two formulas offer both good drainage and adequate aeration for the tree's roots.

[dragon]

May I ask why coconut coir is not good in this case?

[brian]

Because he mentioned "peat (or coir)" I assume he's lumping them together and saying you effectively have a 100% moisture retaining potting medium when it should only be 20% so. 

[Millet]

Dragon, what Brian is telling you is correct.  Nothing is wrong with coir.  The problem is making a medium out potting soil and coir, both products are moisture retentive, both are the same texture and  size will eventuality compact into an airless mixture.  It is much better to make a medium out of 2 or 3 products of different size, doing so promotes moisture retention, drainage and good aeration.   That is why bark chips is so frequently used.

[dragon]

Dragon, what Brian is telling you is correct.  Nothing is wrong with coir.  The problem is making a medium out potting soil and coir, both products are moisture retentive, both are the same texture and  size will eventuality compact into an airless mixture.  It is much better to make a medium out of 2 or 3 products of different size, doing so promotes moisture retention, drainage and good aeration.   That is why bark chips is so frequently used.

Thanks for explaining , Millet. By the way, what kind of wood chip I should buy to mix with potting soil? Please advice.

[Millet]

Most people use pine wood chips.  Probably because pine is a very numerous species, easy to find and inexpensive. I read that a ready to use wood chip sold in bags is sold at Pet Smart stores.  I believe it is called Reptile Bark or RepiBark (anyway something like that).  You could use red wood, or cedar.   I would not use a hard wood product. 

[dragon]

Dragon, what Brian is telling you is correct.  Nothing is wrong with coir.  The problem is making a medium out potting soil and coir, both products are moisture retentive, both are the same texture and  size will eventuality compact into an airless mixture.  It is much better to make a medium out of 2 or 3 products of different size, doing so promotes moisture retention, drainage and good aeration.   That is why bark chips is so frequently used.

Thanks for explaining , Millet. By the way, what kind of wood chip I should buy to mix with potting soil? Please advice.

Again, thank you for giving me helpful information . I have bags of cedar for mulching , next time I will mix with potting soil as you mentioned above.

[Millet]

Chips about 1/2 to 1 " is about the right size.