Hardy Tropicals UK

I'm growing a few Passifloras from cuttings or seed - caerulea, violacea, mollissima and some hybrids.

They're all growing upwards as single stems, some nearly 6ft long (haven't reached the height of the fence yet), and I would like them to branch out to cover the fence like they're supposed to. I'm wondering if they will branch out naturally or I should encourage them by removing the growing tip? What would be the optimal height to remove the growing tip at?

With passion flowers, I normally halve the height when planting out

otorongo wrote:I'm growing a few Passifloras from cuttings or seed - caerulea, violacea, mollissima and some hybrids.

They're all growing upwards as single stems, some nearly 6ft long (haven't reached the height of the fence yet), and I would like them to branch out to cover the fence like they're supposed to. I'm wondering if they will branch out naturally or I should encourage them by removing the growing tip? What would be the optimal height to remove the growing tip at?

Who said they are supposed to, the fact that they are going straight up means that is what they are supposed to do! Not what you want them to do. The optimum height for them to branch is is the height at which you want them to. They will branch below the point you cut them off. That is your decision. Good luck.

I should just add most plants shoot from the 2/3/4/ growing points immediately below were you pinch them out.

I don't know if it would work for all species of passiflora or even if this is what you're "supposed" to do but...

In my first house I planted out a Passiflora caerulea which did the same, it kept on growing longer and longer. I got fantastic coverage by NOT taking off the growing tip but by training it horizontally back and forth across the area I wanted covered till it got to the top. Each year it grew long sideshoots dripping with flowers which completely covered the wall. I cut those sideshoots back to a couple of strong buds early each spring a bit like a series 2 clematis. It always got loads of comments from people asking how I got so many flowers on it.

Sounds good to me. After reading this I realised i had a Passiflora growing up a Trachycarpus that I wanted to branch out, so I pinched out the top. Mine has only branched from the top 2 leaves, I was hoping for more.

climbers need to be grown horizontally for the hormones to encourage side shoots

Mr List wrote:climbers need to be grown horizontally for the hormones to encourage side shoots

This is true for most 'normal' plants and it's called apical dominance. A higher concentration of hormones in the top growth bud puts lower buds into dormancy. When you bend a plant horizontally, the hormones even out, bringing the rest of the buds out of dormancy and thus shoots will grow from what were the lower nodes.

Vagetarian wrote:

Mr List wrote:climbers need to be grown horizontally for the hormones to encourage side shoots

This is true for most 'normal' plants and it's called apical dominance. A higher concentration of hormones in the top growth bud puts lower buds into dormancy. When you bend a plant horizontally, the hormones even out, bringing the rest of the buds out of dormancy and thus shoots will grow from what were the lower nodes.

Well you learn something every day.

Mr List wrote:climbers need to be grown horizontally for the hormones to encourage side shoots

That explains what happened with my P.alata this summer. Many thanks!