Murrayas like well drained soil with lots of organic matter. I'd dig in a heap of something like spent mushroom compost or whatever and use more of the same to mulch the root area of the plants and water deeply.

They generally only need fertilising in spring but it sounds as though they have had enough for the time being. If the compost sparks them up, leave them until next year (spring), dig the old mulch in with an application of complete fertiliser and remulch.

Minerals in soil seems to be a very complex matter and I gather there is a danger of adding too much of one mineral which can prevent the take up of another. It's all a bit too much for my brain cells. For me, better to use a complete fertiliser in which the right balance had been worked out by some one else.

I have a Port Wine Magnolia in a tub which seems to go through an annual bout of yellow leaves/green veins. I'm guessing that something is being leached out of the potting soil. I dig some homemade compost into the top of the mix, apply a couple of doses of Thrive to provide an immediate boost and apply some Osmocote to provide future feeding and the leaves green up - until next time.

Do you have grass growing up to the murrayas? That might be taking up a lot of the food and water.

You can also try giving them a good talking to and tell them to stop mucking around and grow. Early morning is a good time to do this - fewer people around to hear you.

John

If you aren't on water restrictions, I'd suggest you give your hedge two or three really thorough soakings, a day or so apart, and try and flush the soil a bit.

Ta Damo