I want to cover my pergola with Jasmine. One side of the pergola has trellis and plants can be planted in the ground. Next to the wooden support posts (I want to grow up the posts and across the wooden slates at the top of the pergola) I will need to plant in containers. I will hopefully be buying established plants of 1.5-2 metres. Is it best to buy the plants on a trained trellis or bamboo cane? I am very confused and can't see the advantages of either option. Please can you advise which will be best? Thanks.