Blueberry "Tophat" in container???

[Sirius]

Is anyone growing the dwarf blueberry "Tophat" in a container? I have three of them, and they are doing really great. I am slightly concerned about overwintering them though. The containers they are in are easy enough to move, so I was planning on putting them in the garage. We get temps into the negatives in winter, so should I try to keep the containers insulated? I was planning to line them up along the inside wall, where ambient heat from the house might keep them warmer, but our garage isn't well insulated. Running a space heater out there seems really wasteful.

 

[koshki]

Hi John,
I put in a whole row of blueberry bushes last August, and had a few too many for the row, so they all went into pots, including a Top Hat.

The Top Hat is in a gallon glazed pot. I put it inside another pot and tried to insulate the whole thing with leaves, then lined them all up next to the house on the patio. Although we're in Zone 6, we had some pretty cold days last winter. When I unwrapped them all in March, they were all frozen solid, and I thought for sure they were gonners. But they all pulled through.

The Top Hat is growing very nicely. It only had one or two blooms, so I won't have any fruit from it this year. I will probably keep it in the one gallon pot for at least another year. The grower told me to keep them in tight pots.

I've got 7 plants in pots (just one Top Hat), and 8 in the ground. If I'm lucky, we'll only get a couple handfuls of berries this year, but hopefully the will increase in the future!

What zone are you in, John?

 

[koshki]

John, after I posted I checked my container gardening book, and had forgotten some import information.

Blueberries need about 800 "chilling hours" per year to fruit. That is for temps between 45 and 32 degrees. However, once below freezing the plants in pots are at risk of freezing (see above, lol!). I guess I got lucky this past winter.

Anyway, I think putting your pots in an unheated garage to over winter them would work, assuming that they will get cold enough for the winter chill.

I think I may just do that myself this winter. They don't need to be watered.

 

[Sirius]

I am in zone 6 as well. The garage will definitely get below freezing this winter. There are so many variables involved. I don't know how cold my garage gets, but the door lets a fair amount of air in.

 

[PaphMadMan]

Tophat should be hardy to zone 3, -30F. The ground can be frozen solid to a depth of several feet in that kind of winter. There's nothing your zone 6 winter can dish out that should even make Tophat shiver.

Your garage may get below freezing, but does it stay there on a warmer sunny day? If it ever gets above 40F you're in danger of plants breaking dormancy, only to be killed when temps drop again. If pots aren't continuously frozen solid then you will need to water them occasionally. Your potted Tophat would be much better off overwintering outside, in a spot that does not get direct sun but does get rain or snow, with leaf or straw mulch applied after temps have dropped below freezing. The mulch is to keep them cold once they freeze, not to keep them warm.

 

[Lanmark]

I'd sink the pots into the ground and mulch them over for winter, then lift when Spring comes. I don't grow "Tophat" so this is purely conjecture on my part.

 

[Sirius]

After doing a search for container hardiness, I found one reputable source that says Tophat is hardy in the container to zone 5. So you are right, Kirk, I should be good.

As for burying them, well, that is not gonna happen. These are growing in 15" x 15" x 20" deep containers. No way in hell am I digging a hole 46 inches long by 20 inches deep in rocky, Missouri clay. That's just torture.

Blueberry culture information on the web is the most messed up data I have ever seen. There are quite a few opposing sources, and the data is often not clearly divided by type of blueberry, so finding low bush blueberry culture information isn't easy.

 

[Lanmark]

Aha! Missouri rocky clay, aka Misery Clay. :sob:

I'm rather fond of lowbush blueberries. They grow wild in abundance north of here in the places where I spent many of my childhood summers. The species found there are Vaccinium angustifolium Ait. and Vaccinium mytilloides Michx.

I think I'd like to try growing those Tophats! :drool:

 

[koshki]

Yeah, I'm like John...if I had the room in my garden to sink those pots, they'd be in the ground already!

But thanks for the info on the cold hardiness! I may just keep them in the same spot this winter.

 

[SlipperFan]

I gave up on blueberries -- the deer apparently liked them down to the roots!

 

[koshki]

Bummer!

No deer here, but I am thinkin' it's wabbit season...something keeps eating my rabbit-proof perennials, and I'm going broke replacing them!