In July 2015 I had a bit of fun seeing how fast Hablitzia tamnoides, the Caucasian climbing spinach, was scrambling up the trellis on the garden wall. I posted the results on Stephen Barstow's Friends of Hablitzia tamnoides Facebook group. 40cm in 3 days - more than 0.5cm an hour!
I've just repeated the experiment and the photos are below. The first shot shows the whole plant - well most of it anyway (the one with large, light green, heart-shaped leaves). Its top shoot can be seen above the trellis in front of the ivy. There are more shoots in the vegetation below, held back from climbing the wall by our harvesting. The stumps of harvested shoots take a little while to recover but after a few weeks will sprout from multiple places along their length. A mature Hablitzia plant can be very bushy and produce plentiful harvests over the season.
The following photos show the growth over the last seven days of a lesser shoot which is scrambling up to the left of the tall one. (The head of the screw on the second bar of the trellis is a useful reference point for comparing the shoot length).
The growth rate of this shoot over these seven days has been 40cm in 166 hours. A mere 0.24cm an hour! (but then this wasn't the leading shoot and we are in May and not July).
If you have one, how fast does your Hablitzia grow?
N.B. I sell a range of perennial vegetable plants on my website.