On Mon, 11 May 2009 13:40:41 +0100, Charlie Pridham
wrote:

Bob, how big was the root system you planted, if this was small then
plants can take an age to establish, as a general rule anyone buying a
clematis plant of less than 2lt root ball size should grow it on in a
container until its made more root before planting out.
If they were big plants then the problem may be lack of water

The cursory web search I did before coming here bears out exactly what
you're saying - in fact I think one writer was recommending buying
plants mature enough to be sold in 1 gallon pots just to avoid the
wait. I'd say my plants were in a 1 litre pot so definitely on the
small side.

Thanks for the explanation, Charlie.