For the past two years, I have grown 36"-40" dahlias along the south side of our white, stucco cinder block barn. I'm in zone 5A, but there seems to be enough of a warm microclimate in that bed to protect them through the winter. I don't do anything special to protect the bed. When I planted new tubers this summer, what a great surprise to see last year's plants come up too. Since [so far] I have not had to dig and store the tubers, what is a good practice for a warmer zone.

Welcome to OG jrp,

If you want to experiment how about either digging some to store and heavily mulching the remaining tubers or take a shot at heavily mulching them all and see what happens next year?

As you probably already know, dahlia tubers are only hardy from Zone 8 (maybe in certain parts of 7B) and beyond. Sounds like you do have yourself a nice little microclimate there. But even in warmer climes, I think they should be mulched anyway. It certainly couldn't hurt. Let us know how they fared next season with whatever method you try.

Great Question!

I planted some cannas this summer. Similiar treatment as dahlias. Know I should dig and store here, but... Was thinking I might be able to get away with just mulching. Not as protected of an area as I would like, but...
I might try it anyway. Bought at Lowes and they consider it a perennial on the marker. Hardy to 0 degrees. Never heard of a canna hardy to that temp. Saved the receipt. Still debating this.
Lowes honors dead perennials for a year. Bought it in July, so enough time to find out if it will come back or not.

What do you guys think?

lisaann

I think you're wise to hold onto your receipt.
I never heard of a canna (or a dahlia) tuber being hardy to 0 either.

Simply because your air temperatures reach the 0 range does not always mean your soil will too. If the soil is in a protected area and well mulched you could keep it around 35 to 40 degrees even if the air temperature gets down to 0, unless the air temps stay in that range for quite some time.