PH7 is not Alkaline, it's neutral. What kind of plant is this? If you want Alkaline soil. Lift it out of the ground & replant it again with garden lime. Add some lime to the planting hole & backfill & add some around the base. You can use burnt wood ashes or just get some at the garden center. You can also pick up a PH test kit.

Also, when replanting, be sure not to plant it too deeply. The top of the rootball should be level with the surface.

I see the image is named St. John's Wort - if that is a Hypericum (H. moseranium tricolor, or 'Fiesta' maybe?) they are not at all fussy about soil ph, so its not a ph problem - it looks much more like a drought problem - how long's it been in the ground? If not long, it likely needs a good water.

Depending which variety it is, H. moseranium tricolor is slightly tender, so its also possible the leaves have been caught in a frost, if you had warm weather for a few weeks and then it suddenly got cold again.

It was planted on 10th April. There was a frost about 2 weeks ago and my young acer has also suffered! As you stated Bamboo and Bjs, I think that has been the problem! Thank you Bathgate, I am going to replant and add some lime.........hopefully now the warmer weather is coming in, it should start to flourish.

That's good. Once you get it sorted out, the frost won't bother it as much.

Do not add lime for this plant - a ph of 7 is perfect for it, and although they're not that fussy about ph, they do not appreciate extremes, either acid or alkaline, as mentioned here if you scroll down a little bit http://www.gardenfocused.co.uk/shrub/hypericum.php