I saw these for sale a while ago, they seemed cheap, and very cheerful, so I bought some.
"Soft Twist Ties" they state on the pack, as though "Pipe-cleaner" is under copyright.
I tried them in a few gardens, and my, they were easy to use!
Soft on the hands, obedient - they stay where you put them - and they seemed to be strong enough to do the job, but soft enough not to damage the stems of the plants.
And occasionally they cause hilarity, when the Client says "OMG, look at the size of that caterpillar!"
So I started referring to them as caterpillars.
But a couple of months later:
They are metal inside, and it has rusted.
Not very pretty.
Furthermore, I have found that after a year, the rusty ones just break, they just fall apart, so the plant falls off the wall/wire/trellis.
I've spent the last month hunting them down and replacing them with dear old Soft Strong,
This is by far the best product I've found for long-term tying of plants to supports.
It's plastic, which is not very eco, but it stretches, so it doesn't strangle the plant: it lasts for decades, can be undone and re-used, does not go brittle in winter, and apparently never ever breaks once it's been tied!
(I have broken a few bits by stretching them too far, especially once they've been outside for a couple of years, or when it's very cold)
Available for sale via my website, here's me being lazy and just putting up a link!
It's £2 a pack, each pack contains 12 ties, each 7½" (18cm) long, UK only, payment by Paypal.
To order, email me - my email address is at the top of the page, on the right.
In summary then:
Caterpillars = OUT!!
Soft String - IN!!!!