We never fertilised our cuttings during the rooting process. Nor did we have a lot of fertiliser in the soil mix when they were potted up, until management changed and increased the amount of fertiliser in the soil mix to force the growth. Forced growth is not good - it produces a less attractive plant with longer internodes (the spaces between the nodes) and therefore a less bushy-looking plant.

Come to think of it, when potting up rooted cuttings, when we had a cutting or two that weren't as sturdy and strong as the others, we would often put two of the weaklings together. Maybe you could do that with your less than sturdy cuttings.

Thank you for your view, tete_a_tete. I think the clem babies I lose to winter usually look just as sturdy as others that do make it. Apparently they are weaker though, or less cold hardy, or could be both. Most of the parent plants of these are strong growing varieties. At the point when they fail to resume growth in spring they are perhaps 9 months old so I don't think fertilizing them would be injurious. I'm thinking about trying to grow them over the winter indoors under lights.

Ah, I realise finally what you mean. I agree with you - it was probably a mistake to throw away rooted cuttings that had no top growth.

As to the best thing to do, I don't know. I'd be interested in hearing of your experiments.

All I can think is that it gets too cold for them outside. If they stay green all winter and never lose their top growth I guess they'd be ok. ( grown indoors) Maybe they would lose their top growth but not go in to cold shock or whatever it is. I wondered whether there was some vitamin or substance other than the usual fertilizer ingredients that might jolt them into top growth. I know bigger clems in the ground can disappear even for a few years and then reappear. What makes them come back?

Have a look at the cannabis growing websites...which invariably have a range of bio-stimulants such as fulvic and humic acid, myccorhizae (which would definitely benefit clematis transplants) and various mineral additions such as zeolite, rock dust and so on. The cannabis industry has given rise to some of the most innovative practices in horticulture |(such as carbon dioxide capture, for example). Obviously, you will have to deal with a degree of boastful bombast and snark but the knowledge is there.

Oh, thank you for these ideas, HU. It would be wonderful if I find some way to help these babies. I almost gave up on rooting them this year but I do want to see if there's a way to help the balkers. I will print out your suggestions. I still have some with good roots and no top growth so maybe even those are worth a treatment with something.

Seniorballoon, I hope you'll let us know how yours do over the winter with the heating mat. I should bring some of mine indoors tonight as we're getting a hard freeze. I looked at my original post from about three months ago and I said that one clem that appeared dead had just recently put out some growth. So that was about late August or early September. The other little clems had started growing roughly in April. So that was a lag of about four months of sitting there looking dead.

I do not think the heating mat was a good idea. I noted that several were looking poorly and used a thermometer to check the temp at the bottom of the pot. 120 degrees? While checking this I also realized it was causing the pots to dry out from the bottom up. I'd been checking the moisture at the top of the pot and only watering when looking dryish. I fear that I not only cooked the roots, but let them dry out. Won't know for sure until we get a bit more into spring, but most of the clems look dead. :o(

I would be interested too, on what becomes of a clematis with no top growth. I had some in Alaska stay underground and I figured it was the cold there. Here I have had a top die off and wondered if they make a new top, but have not seen them come back yet.

It may depend on how well established the root system is. I have cut back hard clems with a robust, well developed root system and they always come back. It will not necessarily happen immediately - could take a season or two - but they will come back. As long as the plant is treated like an actively growing clem. I have had various clems remain what I call "dormant" for several growing seasons before springing back to life.

Seedlings or small, cutting grown plants may not have the same response given they will also have a correspondingly small root system as well. But I wouldn't give up on them.