The calendar says we are still in the fall season, but winter conditions have hit hard and fast over the last couple weeks across the United States, catching a lot of dahlia gardeners off guard. In some parts of the country, it went from an Indian Summer to winter snows in what seemed to be overnight.
Wait until your dahlia foliage looks like this before digging in the fall
The challenges with dahlias is that they need to feel a few freezes in order to properly end the season and cure their tubers. When we let our dahlias freeze in the fall, that tells the plant, “OK, it’s time to go to sleep for the winter.” Then the stalks turn black, the energy is returned to the tubers and the tuber skins begin to thicken as the tubers are preparing themselves for winter. It’s risky to dig your dahlias before a freeze. Dahlias dug too early have thin skins and typically do not survive the winter. They may look alright now, but usually by spring, they have shriveled to an unusable tuber. Dahlias are a plant of patience and need their time to do what they do in order for them to survive winter.
But what if the cold weather hit too soon and now your dahlias are buried in snow ? Well, that is the unfortunate part of Mother Nature. You never know what she will send your way. If you are buried in snow right now, chances are Mother Nature has beaten you this year. It’s time to plan on ordering some new dahlia tubers for the spring. If you didn’t get any snow, but your soil is frozen, wait until the soil has thawed so that it can be somewhat worked, dig up your clumps and see what you’ve got. If they look dark brown and have a ‘clear’ look to them, they are frozen and should be composted. If you see a more fleshy whiter tuber, it may have survived the deep freeze.
The benefits of mounding your soil
Just like we plant potatoes in mounds, dahlias benefit greatly from being in mounds as well. This will accomplish a few things:
1) When you dig in the fall, if you’re having a rainy fall the dahlias will be up and out of the wet mucky soil.
2) If the temperatures fall drastically like they did this year, the top few inches of soil will be frozen. But if you dig down, you’ll find the dahlias are in unfrozen soil. As long as you can remove the crust on top of the mound, your dahlias should be fine.
3) Mounding your soil will provide better drainage and warmer soil temperatures than dahlias planted down in the soil.
Mounded Rows