Question
I think I may have made a grave era. 9 months ago i had removed, a quite large and old lawson pine hedge. I have since planted 4 Melia azaderach trees 2m high and under planted this with Star Jasmine. they have been in for 3 weeks and all are looking unwell. I tested the soil today with a home testing kit and the result was alarmingly acid- 4.5 ph. I will repeat the test but I obviously need to take drastic action. What action should I take. Any advice appreciated. Thank you. Regards Jan.

Answer
Hi Jan,  I'd use a little hydrated lime (per label instructions) and get the pH up as quickly as possible.  You'll probably need at least two applications.  Check your pH two weeks after the initial treatment to see how much improvement has been made.  The target pH is 6-6.5.
Hopefully, your plants will recover quickly.  
Monitor the pH every couple of months until it stabilizes.
Jim