If the clematis is planted deep, it will force the plant to grow new stems from the crown. Did you plant it deep? At least six inches.

Yes, it is the deep planting, together with hard pruning the first two seasons, that encourage clematis to produce multiple stems from the root crown. Fertilizing with a product that contains alfalfa or using alfalfa meal will also encourage additional stem development, due to a natural plant growth hormone in the alfalfa.

And sometimes, even doing all of the above, it is a factor of age. I would generally not expect any clem to be very productive for the first 3-5 years after planting.

After killing one clematis, I did more research before planting this one. It’s in a more suitable location (I hope), I planted it deeper and angled toward the trellis. I suppose at this point it is just a matter of maturity.