Sweet peas are lovely with a powerful scent and a wide range of colours. We grow them both for their beauty in the garden, but also to pick and bring indoors. For Sweet peas to look good on the plant, and in the vase, Sweet Peas need to have straight stems. This is easy to do.
First, if you want long straight stems, the variety you buy will make a difference. The old-fashioned Spencer varieties are good and it is worth checking the seed packet to see how the varieties is described. The variety 'cupani' is pretty, but it has shorter stems although they will be straight.
To get straight stems on sweet peas, the tip is to remove the tendrils. When you look at a Sweet pea, you will see the tendrils, which cling onto the plant support and look as if they are helping the plant along; they are not.
The tendrils will cling onto the support but also onto other parts of the plant, which causes the plant to become twisted and bent and this mis shapes the stems. As the summer goes on the plant produces more and more tendrils, which wind and cling to all parts of the plant, and so will bend and distort the stems more and more. If left unchecked, there will only be a few straight stems on the plant, and the whole plant has become all bunched up and looks a mess.
The answer is to remove the tendrils every few days or at least once a week. Doing this many mean that the plant may flop and need some support to keep it growing upwards. It also means that you will have lovely straight stems on the flowers you pick and a plant which keeps growing upwards and covered in lots of lovely straight stemmed blooms.
See also How to Grow Sweet Peas and Sweet Peas and mildew.