4 yr.old autumn clematis grows really well but no buds or blooms. What gives? The autumn clematis is planted in full sun, in good soil, by the porch for it to climb on. I have tied it up and it gets good moisture. It's growing beautifully but never flowers. I understand it blooms on new growth, so it gets pruned back in late fall. Help. Thank you.
Clematis Not Blooming
Certified GKH Gardening Expert
You likely have an imbalance in your Nitrogen/Phosphorous levels. To much Nitrogen will cause lush greens and no flowers.
You can add a Phosphorous fertilizer like Bone Meal to help promote flowering.
Here is a link with more information.