You need more for them to climb than just the post of the hooks. Wire mesh for example.

Many will grow too large too, keep that in mind. You do not need to worry about "cool" roots. That really means moist not shaded. Clematis are not drought tolerant.

I have been to a private garden with a hundred Clematis and many are growing up posts topped by bird houses and feeders. There is no problem with the birds.

In my experience you would want to avoid using sunflower seeds with the hulls on in your bird feeders if you want to plant under the feeders. There is an allopathic compound in the sunflower hulls that discourages many plants from growing, and while I am not sure that it would affect clematis, I've found in the past that very few plants are happy under feeders that contain unhulled sunflower seeds since as the birds feed, the hulls drop onto the ground under the feeder, leaving the allopathic chemicals to leach out and discourage any other plants' growth. I think other bird food varieties would be fine, however.

I also read that about sunflower seeds. I use all sunflower seeds and my feeder had 2 "fairy rose " bushes and many day lilies around it and they did great. However, I planted two different Clem's there and they never took off. They were 3 feet tall , max for 3 years! I didn't know if the roses shaded them too much and they never had a chance or what. So maybe that compound leaching was to blame?

Here's a pic of the feeder and the plants that did well around it. Also ,A big perk to the very thorny rose bush, was the neighbors cat didn't mess with the birds there and the squirrels had to make lots of effort to jump up there.

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