Dear Dahlia Doctor – Must I Dig Out My Tubers?

Dear Dahlia Doctor,

Just planting those tubers was a lot of work. Do I really need to dig up each and every single tuber and then go through the process of storing them? I don’t have space nor do I have all the necessary supplies to store them.

What are my options for leaving them in the ground?


- Tired of Digging


Dear Tired,

Yes, you can leave your tubers in the ground. Just be aware that as dahlias grow, so do the tubers – and having a large clump isn’t necessarily a good thing if you want healthy flowers the following year. Tubers also suffer when Jack Frost comes along or when the ground gets soggy, like it frequently does here in the PNW. These are all things you need to take into account when planning your garden. It is perfectly alright to leave them if you’re just growing them for fun, but if you have any intention in showing your flowers, well then, it would be best to dig them up. If you have questions about that, just come to one of our Seattle Dahlia Society meetings and we can walk you through the process of digging up, cutting and storing your tubers for winter. Just shoot us an e-mail in August or September and we will let you know at which meeting we will be discussing and showing how to do this.

In the mean time, if you are okay with just keeping your tubers in the ground, you can leave the ground as is or you can cover the area where your tuber is planted with leftover Bubble Wrap from any recently purchased fragile items or packages that come; heavy duty plastic works well, too. You can also use old table cloths – oil cloths work well, too. This will add a layer of protection for when Jack Frost comes to visit. You can probably do this in November/December, depending on when winter actually comes to the PNW. This may not fully protect your tubers, but it will help insulate them from the cold.

Dear Dahlia Doctor – My Dahlias are Wilting in the Heat

Dear Dahlia Doctor,

This is my first year planting dahlias and I have a lot to learn. My plants (below) are huge but nothing has bloomed yet. The tubs I’m using seem too small, which I’ll need to fix next season.

Dahlias suffering because of the hot summer

Seattle isn’t supposed to get this sunny!

Right now I’m worried because lots of leaves are drying in the heat and I’ve been trimming them off. I’ve been watering every other day because it’s too hot. Are they okay? Will they still bloom? When is it normal for them to bloom? What should I do to treat them best?

Wilting in the Uncommonly Hot Seattle Summer

Dear Hot Seattle Summer,

It would probably be a good thing for you to water your plants daily if temperatures are higher than average or if your leaves are getting sunburned.

There are some easy things you can do for your dahlias during August and September to help your blooms be the best they can be.

  • Keeping your plants well watered during hot weather is important; if the leaves are still drooping as the evening cools, be sure to supply enough water so they regain their turgid form.
  • Make sure to water early in the morning or in the late evening when the temperature is cooler.
  • Break off the lowest leaves to allow air to circulate under and around the bushes.
  • During hot weather, fertilize during the coolest part of the day (early morning or late evening).
  • Keep the plants gently tied up to their stakes.

Another possible reason for sunburn on plants is the sun reflecting off of hot walls near the plants. Your plants may need a little shade in the hottest part of the afternoon. Do you have a beach or patio umbrella that you can put up to help those pasty, plaid-wearing Seattleite dahlias survive the summer sun?
If the tubs are easily moveable, you might try relocating them to a shadier area of your patio.

The good news is that stressed plants will still bloom it’s just the number and quality of the blooms that will be affected. Maintaining a garden is usually a learning process – green thumbs don’t grow on everyone and transplants are expensive even with insurance, so don’t worry if something doesn’t grow the “right” way the first time around.

Hope that helps you, I’d hate to imagine the bill for all the bottles of SPF 100+ sunblock you’d otherwise have to purchase to cover all those leaves!!

- The Dahlia Doctor