I have later summer blooming clematis I want to move out of the shade this year and into the sun where it will be happier. I now a good time to move it? I have read conflicting advice on the internet, some say now is good and some say wait until after blooming,
When you say “later summer blooming”, that could cover many kinds of clematis. But what is true of all of them is that their flower buds are produced on current season or new growth. These vines can be pruned in late winter or very early spring. This gives the vine plenty of time to produce flowering shoots. The same principle can be used to determine transplant time.
You also don’t say how long the plant has been in its current location. Moving an older, larger plant will be more challenging than if it has only been growing in the shady spot for a year or two.
Here is a link to our answer to another Toronto gardener, who wanted to move a late summer / fall blooming clematis, the Clematis virginiana, which had been growing for some years.