I don't do anything special to overwinter mine in zone 5b. Some mulch probably wouldn't hurt if you've got the time to do it.

I used to have a buddleia when we lived in the city. I never did anything to it and it survived each winter just fine. Since we bought our farm, I have tried several times to grow buddleia but it never survived the winter, we're in zone 5A but the big difference is that this site is more windy and colder than the subddivision. My last attempt to save them was 2 years ago. I mulched and caged it but it didn't help. Since we have built the house, we now have a sheltered spot where I will try again to overwinter one. Marg

Marric, did you grow the species of buddleia at your farm or was it a cultivar? I'm wondering if the species (I grew mine from seed) is any hardier than the cultivars. I have read that some cultivars are hardier than others. If I'm buying plants I try to purchase the hardier ones. Even so, they might live for several years and then not survive a particularly difficult winter.

Ontnative, I grew my plants from seed and identified tham as Nanho Blue. Do you know that hardiness of these plants?

ontnative - I grew the buddleia davidii seeds that I bought from Veseys. I had this one also when we lived in the city and it lived for about 8 years, still there when we left. Here the site is open, windy and a lot colder. I think it's the winds that do it in. We now have our house up so there is now a sheltered location where I can plant a new one. I've already tried here several times but now that I have a better spot for it, hopefully it will survive. Try, try again!

I had thought I read somewhere that Nanho Blue was one of the less hardy ones, but I looked on Google now and couldn't find anything to substantiate that. Most buddleias are listed as being root hardy to USDA z.5, which is roughly equivalent to Can.z.6. I think "marric" might be correct in thinking that the winter winds are detrimental to them. I planted two 'Potter's Purples' a few years ago, one in my boulevard and one next to the house, on the southeast side. The one in the blvd. died the first winter, while the other one is still growing well. I currently have plants of 'White Profusion', 'Guinevere', 'Lochinch' (?) and of course 'Potter's Purple'. They are all in my back garden, some of them on a hilly slope which is exposed to winter winds somewhat. So far they keep re-sprouting in the late spring, after I think they must be dead.

Northerner,

Not sure if I responded on the mother forum, but I don't do anything to protect my Buddleias. I have two which have returned faithfully for 5 years since I winter sowed them. Others, winter sown 3 years ago, have also returned.

I have some in quite windy conditions, but being on a bay next to the Atlantic is different than being in Ontario. Some Buddleias are fully exposed to the 'noreast', and yet they return to grow to their 6 foot height. Others, same exposure, barely grew this past year and I would not be surprised if they don't return. They are in rocky soil, but those in fair to good soil are doing the best so there is no dobt that soil conditions do play a factor.

I have three newly planted this year which I am watching closely. These were winter sown 2007/2008 and overwintered in pots. They bloomed this year and grew to 5 feet and to my surprise, one of them was white. :O) Seeds were from a trade. They are planted in an area which is wind swept in the winter yet has wonderful moist soil. I will be mulching them today, but not too much.

Wishing you all the best with your B!!

Oh, I didn't know about not cutting them back at first and lost a giant one in year two when I first grew these. Don't even be tempted.

Thanks for the info Tiffy. If I knew how hardy they were I could have saved myself some work. My plants are now enclosed in chicken wire 'pots' about 3 feet high filled with leaves for protection. However, it's good information for next year. I plan to WS a few more this winter since they grow so easily and are such beautiful shrubs/trees. Thanks again.
Northerner.