I have a very old well established garden, which generally has an alkaline soil with a ph of 6- 7. Over the last twelve months I have developed a problem in one corner where I noticed that my established hedge of lilac bushes were dying at one end. The end which is affected has a very large old conifer tree, which on close inspection is also not looking very well. It has lost most of its needles especially up the centre of the tree. This is all around the tree not just on one side and the ends of the branches are the least affected, so I do not think it is wind damage. This spring we did apply a mulch of well rotted horse manure over the whole of the front area, in an attempt to save the lilacs but to no avail. The lilacs at the other end of the hedge appear well and are putting out healthy runners as usual, they also had the manure applied this spring.
Having dug out the dead lilac bushes (three or four) and cleared the ground I tested the soil to find that the usually alkaline soil has become very acid in that corner (ph 4-5). However on the other side of the conifer and around the conifer it remains alkaline (ph 6.3-6.8). What is more I find that the deeper I dig the more acid the problem corner becomes (ph 3) as opposed to the rest of the garden (including around the roots of the conifer) where it becomes more alkaline the deeper I dig (7.1).
What is happening and what should I do?
Do I give up on the conifer and have it cut down?
Is there something I can plant, which will reduce the acidity of my soil in that area?
Will this problem spread?
- 14 Aug, 2008