My Dahlias are Sprouting and it might FROST!!!

These days, the topic of discussion surrounding the dahlia growers' water cooler is when do you plant your tubers? The answer is usually to wait until after your last frost. That is sound advice. But what if you left your dahlias in the ground all winter and they're already sprouting, and a late spring frost is in the forecast? Is it time to panic?! Welcome to my dahlia conundrum of the week.

Carilyn Mae

Carilyn Mae
This morning, I spent a few hours volunteering in the youth garden at Raab Park in Poulsbo, WA. This garden is a fantastic space that Kitsap Master Gardeners tend. They host a summer youth program every year and grow thousands of pounds of produce which is donated to a local food bank. I am honored to be among the Master Gardeners on this team.
This season I am helping out with the flowers, go figure, and today we began rejuvenating the flower garden. Part of that process was digging up and dividing the dahlias. Since I've had a bit of experience in that department, I took care of that task. After carefully lifting the tubers, we hosed them off to get a better look at what we had to work with, and I was very happy to see beautiful eyes were already growing. Many of them were about an inch long. None had broken through the soil surface, but it won't be long. I had about ten clumps to break apart. I plopped myself down on the ground and got to work. Dividing dahlias is a mindfulness task that I love, and it was a glorious day. Not a shabby way to spend a Thursday morning.
When I got home, it got me thinking about the dahlias I left in the ground. How are they doing? I peeled back the wool mulch (Yes, you read that correctly, I use wool. More on that another day) and happily discovered not just eyes sprouting but leafed out new growth! I plan to plant out the tubers I have in storage this week, and here these that were left on their own are already growing! Amazing. This wasn't surprising. I knew that dahlias left in the soil grow and flower much sooner than planted tubers, but it's still great to see them in your own garden.
My joy and amazement quickly switched to concern, though, when I remembered that we had one last cold snap in our forecast...frost.
Dahlia tubers below ground can handle chilly nighttime weather. Still, if a frost touches the tender new green growth, it could kill those young shoots. What should I do? Well, here are my options.
  1. Leave them be and hope for the best. It's possible we won't get a frost, and they would be completely fine. And it's also possible a frost will come and kill these first shoots. However, since these are tuber clumps and not single tubers, I am 100% confident that there will be many sprouting eyes coming out of each tuber cluster. So losing these first few would not be the end of the world.
  2. Cover them. Like other tender perennials, a light covering will keep the frost off and be the difference between dead and okay. I could toss a row cover over my dahlias in the evening and remove it in the morning after the danger has passed. With this method, I'd have to be careful that the fabric I use doesn't touch the green growth. The frost could make it through with direct contact. It doesn't have to be fancy, just something to elevate the material.
  3. Mulch. Deep mulch would be another way to insulate the fresh sprouts. I had pulled my wool mulch away from the tubers to reveal the sprouts, so I could just tuck it back around. That might be enough protection. Compost would be a perfect material for this too.
  4. PROPAGATE!!! I may take cuttings from these plants, pot them up, and make more baby plants. That would definitely be my M.O.
  5. Dig them up. Yes, this is definitely an option too. I could dig them up now, bring them into my garage, and maybe even divide them. Of course, I'd have to be very careful not to break off the new growth while dividing, but that would be a way to multiply my stock. Do I want more plants this year?
So what will I do? I will look at what plants I still have out in the garden. Are there any that I want more of? I may dig or propagate those. The rest I'll tuck in with mulch and hope for the best. With all of the other garden projects I have going on, and knowing these won't be the only sprouts, I'm not going to stress losing these first few stems. That's why dahlias grow into clumps. It's to help the plant push lots and lots of shoots to keep the lifecycle going. If they all sprouted simultaneously, one weather event would decimate the entire population of plants in an area. Yup, I'll use my row covers to protect my spring greens planted in the big garden and let the dahlias fend for themselves. They'll be okay.

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