Question
I have an althea bush/tree in my yard which I planted about 3 years ago.  This season began fine with the plant developing leaves in late March and started to produce flower buds in May.  It is now June 9 and the tree has been flowering just fine for 2-3 weeks.  In the last several days the leaves have been turning bright yellow and then wilting..the yellow leaf development is spreading throughout the tree and about 35-50% of leaves are now yellow.  The tree is about 8 ft tall.  I live in Fort Worth TX and we are now in the mid to upper 90 degree weather.  I have a sprinkler system which runs twice weekly and I hand water the plant 3-4 times weekly.  I have a second althea planted about 20 ft from the first which was planted the same day as the first and it is not showing any yellowing of the leaves.
I did fertilize the plant with water soluble miracle grow just before i noticed the leaves turning yellow.  Any ideas what the cause is and can I save the plant?
Thanks,  Ken  

Answer
Ken,
From the description of the yellowing leaves, it sounds like it could be a few things.
1- Check to see if there are any insects on the lower leaf surfaces or on the bark. Several insects will attack Althea- Whitefly, Aphids and Scale. If you find any, go to your local garden center and they will sell you the proper materials for control.
2- If no insects are found, then it could be either bacterial leaf blight or a canker disease that has infected the cambium layer of the plant. These diseases will need to be treated with direct injection into the tree to deliver the fungicide to where it needs to be. Find a certified applicator who is prcticed in the Mauget, Wedgel or Arbortec systems.
I hope this helps.
Good luck.
Ed Gulliksen