Floppy Hydrangea Limelight

CostumedVole

I planted a Hydrangea Limelight a few weeks ago. It came with bamboo supports, which I foolishly thought were just for security while transporting it, since all the hydrangeas I have, including the many I have grown myself from cuttings, have been solid and hefty enough to support themselves. It was in flower and has five or six large flowerheads. Tonight I had to dash out in the rain and stake it up again because the torrential thunderstorms had dashed it completely to the ground. None of the stems were broken and it's securely fastened up now, but I'm wondering if this is how it will always be, or whether it will harden up and be self-supporting. I know that growers force plants into flower early and I wondered if it was just too young a plant to support so many flowers. If so, will the stems harden up for next year? Should I prune it in March to get new growth? If I don't, will the current stems just get longer and remain floppy? Please advise. I don't usually have problems with hydrangeas.

Fairygirl

Limelight is a paniculata, and they usually get pruned back hard each spring, to flower on the new growth. The flowers are heavy, so many people leave a small framework of mature stems to help with that. Gradually, the main framework will be tougher, and will support the new flowering stems more easily. 
How hard you prune next year will depend on the maturity and size of the plant too. 

It's also worth growing them 'hard' and not overfeeding, so that they don't produce lots of soft growth, which exacerbates the problem.

CostumedVole

Right, I see. I think. Thanks for replying. If it currently has 4 equally sized main stems with big flowerheads and 4 shorter, thinner ones with smaller, still developing flowers, what would you suggest I do in March, on the assumption that it doesn't grow any more stems?

Obelixx

I agree.  The paniculatas have very heavy flower heads for young plants to support, especially in adverse weather.   The form Annabelle is notorious for being floppy but breeders have managed to create one called "Strong Annabelle". 

Fairygirl

I don't want to advise you to cut back hard without seeing the size of the plant. It sounds quite immature. 
March is quite early. Pruning needs to wait until there's no chance of frost. End of April normally here at least 

CostumedVole

'Strong Annabelle' sounds a bit like a kids' cartoon character. 

Here's Weedy Limelight, before I kicked its crutches away.

Fairygirl

Yes - it's a lot of top growth, so it's best to keep it supported for now until it's established. Just planting them out can be a shock because the root system isn't secure enough to support the heavy flowers and all the foliage.
You should be able to cut back in spring to a pair of good buds. Normally you'd do it to around a foot or so, but here's a link anyway, so that you can decide the best height when the time comes.
https://www.rhs.org.uk/advice/profile?pid=516

CostumedVole

Thanks for that. I can see I have to relearn what I'm used to with my old-fashioned hydrangeas. I'm always a bit secateur-happy, so I will no doubt prune it hard. Treat it mean to keep it keen. I never think of feeding things, so it needn't hope for luxury. I shall keep it propped up until I cut it back in, shall we say, late April? Don't want to leave it too late and accidentally lop off the flowers, nor do it too early and watch it crisp up like my others did this year with the late frost. Nor do I want to see it flop all over the ground. I bought two dwarf Limelights at the same time to put in planters and they seem much more capable of looking after themselves.

Fairygirl

It really depends on your climate and conditions. It can't be helped if a late frost happens. That's gardening.
In most years, if you can usually do Hydrangeas in March, they should be fine. 

CostumedVole

Yes, that is true. Manchester weather isn't usually too cold, at least not compared with where you are, and although it is rainy, it's not the rainiest city in the country by a long chalk. (Hello, Glasgow, I believe!) Most things tend to stagger through somehow, although that's perhaps because I don't plant anything challenging. I shall make a note to do it in late March and play it by ear.

Fairygirl

Yes - you'd probably be fine, but that's when it can be useful to make notes each year for that sort of thing. Gardening tends to make you aware of weather and climate a lot more!
I worked outdoors for a very long time, so knowing my climate was something I was used to, long before I gardened seriously.
I'm not in Glasgow itself, which also makes a difference, but we're certainly on the wet side of the country. Cooler climate, so ideal for shrubs like Hydrangeas, Rhodies, Camellias etc. as well. Our average annual rainfall is around four feet.