I'm growing hydrangea anomala subsp. petiolaris over the garage doors, and Louis the Plant Geek's explanation about how this plant grows was really instructive.
Through careful observations he noticed that this beautiful vine grows very slowly unless the stems, called travelers, can latch onto a surface. Once they are firmly attached, they put out flowering side shoots and make a full, leafy, flowery show, and then the plant grows rapidly. But making the searching traveler stems grow without much to hold onto is a recipe for patience.
That explains a lot. I've been very patient.
In 2006 (yes, that was ten years ago) one of my retirement gifts was a good sized climbing hydrangea from a local nursery.
I decided it should grow straight up to reach the top of our garage doors, where we had a pergola installed. Then it should scramble horizontally across the pergola. I thought I could just take the long vining stems as they grew, and tie them to the pergola. Like a big old rose or ivy maybe.
But the stems are very brittle and they didn't grow in long canes. Sitting well below the pergola, they seemed disinclined to grow up toward it. I put the whole twiggy thing inside a wood tower, thinking that might offer some support at least. You can see those initial traveler stems searching for something flat and rough to attach their holdfast roots to as they probe the air outside the tower.
The travelers finally decided to make their living by attaching to the laths of the wood pyramid, and so the hydrangea started to fill out but would not grow upward. Its growth rate was slow. Not much happened in the way of flowering.
Over the next 9 years I struggled with this hydrangea. It didn't want to leave its tower. It grew, slowly, filling out to the sides, but always firmly attached to the wood laths of its cage.
I eventually hung a long vertical piece of lattice off the side of the pergola and finally got tips of some of the travelers to touch it. That worked. The travelers explored it, they attached some rootlets, they leaned on it a bit, but it took more years before the stems would attach firmly enough to send up real growth.
The climbing hydrangea reached the sturdy support of the pergola in 2013 and then it began sending out side shoots all over and flowering. It has started to scramble across the pergola.
When the leaves are down the peeling bark is beautiful. Birds nest in the interior. Where traveler stems are firmly attached to the pergola at the upper reaches, side shoots have formed and flowered.
In 2015 I finally took the tower cage down. I had to cut it away from the inside, carefully working around the firmly attached vines. Here, in early spring last year, it was finally freed.
This winter I wanted to expose the peeling bark and the beautiful twisting architecture of those original traveler stems on the lower half. That's what I did on a mild winter day last week, opening up the congested tangle of stems below and pruning away leaf buds. I have to strip away more leaf buds, though, to really clean up the look of it at the bottom.
All the side shoots and flowering will be at the top, all across the garage doors.
With the branches bare now, I can see how flowering side shoots radiate out from a large traveler that has reached the top. You can also see my attempt to bungee-cord a traveler to the strut of the pergola. If it touches the strut it will make rootlets and attach itself, and start to radiate side shoots, so I'm going to have to get that brittle woody stem to actually touch the structure.
If I had better understood how climbing hydrangea grows when I planted this, I would not have attempted it here. It's taken 10 years, but I'm glad I didn't know better.
The problem now is that the pergola structure has weathered and deteriorated over 10 years and needs painting. Significant cracks have developed. It may not last long enough to hold the climbing hydrangea up.
Then what do I do? Would bungee cords hold that split post together?
I do have bungee cords. And I know how to use them.