I planted 2 clematis back in early April. They are 2 differnt
varieties, but I can't find the labels at the oment so i can't say
what they are - sorry. Both did really well initially, putting out
lots of growth and climbing well. Then one stopped growing and showed
some yellowing on the lower leaves, while the other thrived and has
about doubled in height. This one has now also stopped growing and is
beginning to show yellow leaves. Any ideas?

Sam