How do I protect a Buddleja colvilei in the winter?

I've planted a Buddleja colvilei in a well protected corner, but I want to give it extra protection in the winter. How? Do I need to pack it with straw or some other material?

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@Howard Stone Whereabouts in the UK are you?
it should be fine without extra protection.
My B colvilei has been outside in a bed since about 2015 and has thrived.
The RHS have it as H4 hardy throughout most of the UK -5 to -10°C.
You might want to consider moving it next year as it gets quite big, mine is 10ft tall and quite spread and I know of one in Cornwall that has formed a small tree with a 6-8ft trunk. Unlike many Buddlejas that flower on the current years growth; B colvilei flowers on older wood in spring time and if pruned like B davidi you will get no flowers.

 

Buddleja colvilei is quite hardy, as Nigel says. And it gets hardier with age and size. Typical for these mountain Buddlejas, it actually needs some cold exposure (not freezing) to flower properly. It also doesn't like it too hot or too dry in the summer. Winter protection is probably not necessary, but covering with a light fleece if you're expecting a really hard frost can help protect the latent flower buds, which form on the previous year's growth.
The biggest killers over winter are water waterlogging, even though it likes wet summers, and vine-weevil grubs.

 

Wimbledon. It is against a proverbial warm wall in Surrey!

There used to be a pomegranate in the same spot for about 10 years. It produced copious healthy foliage, I never saw a flower but I did see a fruit -- just one, less than a centimetre diameter. I'm now wondering, as per the post from The Buddleja Garden, the flower buds were killed by cold weather in the spring.

 

Thank you gentlemen for these experienced and reassuring replies

 

Well, still now flowers, though lots of growth.

I think I'll rip it out.

 

It's still a bit early - some of mine have only just shown flower buds forming. I would check carefully, as the small buds may still be hidden by leaves. It is a species that only flowers when it chooses to and it's possible the position doesn't suit it.
I have been growing seedlings for years without getting flowers, when the named ones have been flowering well. Once they start, they tend to flower most years. So I wouldn't be too hasty.

 

Thanks, I'll give it a few years more.

 

I just looked out of the window and nearly had a heart attack when I saw this. Am I actually going to finally see the most beautiful flower in the Himalayas?

 

I would put money on that actually being Buddleja forrestii, which flowers now. Buddleja colvilei flowers in May-June.

Here is a photo of what I think the flowers will look like:


Which came from a bud just like the one you show. But please keep us updated on the flowering!

 

Will do @The Buddleja Garden I'm pretty sure I bought it from Mallet Court Nursery, it was sold as B. colvilei "Large Leaf Variety" though that one is no longer listed.

Buddleja forrestii looks very nice.

http://malletcourt.co.uk/wp-content/uploads/2023/09/Mallet-Court-Catalogue-2023-Web-Version.pdf

 

Did the flower open? What was it like and does it look like B. forrestii?

 

Yes, just yesterday in fact, I guess it was waiting for the rain. I'll upload a photo later, but it is indeed very like Buddleja forrestii.

Should I prune it hard in the spring?

 

That's a tough one to identify, but I would say that is possibly Buddleja macrostachya, the summer flowering form. Most likely a collection by Roy Lancaster from Yunnan: SBEC 360

B. forrestii blooms just a little earlier and the individual flowers are shorter, funnel-shaped and a completely glabrous exterior to the corolla tube.

Absolutely do NOT hard prune in spring. The flowers come on new wood, but the new wood's buds are already there by winter, although completely undeveloped and dormant.

A photo of SBEC360 at Westonbirt: