compost

My compost bin is next to the roots of my Clematis Armandii, which I planted in Spring 2015.  it grew really well and had covered the whole length of wall but suddenly started dying back during July, August.  i left my hosepipe running into the roots regularly, thinking it may be drought, but it's not looking much better.  A friend suggested that the compost could be affecting it.  I did put quite a lot of citrus skin after juicing, at first, but then stopped that, the bin is full, newspaper and raw veg waste, etc, no animal products or anything cooked.