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

Dear Dahlia Doctor – I CAN’T Keep The Slugs Away!!

HELP! Dahlia Doctor!!

The slugs! They just keep coming and coming!! What do I do?! What can I do!

Slug War Soldier

Dear Slug War Soldier,

Those pests seem to keep coming back no matter what we do.

Here are some solutions that you can try:

  • Egg shells – break up some egg shells and spread them around your plants. Slugs don’t like sliding across them.
  • Chalk – grind it up and spread it around in a thick border. Not only will this give plants a calcium boost, but those slimy slugs won’t want to cross that line!
  • Beer – the standard beer trap works wonders. Get an empty can of tuna fish or cat food and fill it with beer; set it out in the evening. Let those stinkers know that the party is at your house this summer and then pick them out and toss them out in the morning. You can also share some beer with the flowers, I’m sure they’ll thank you, too!
  • Cups, Pringles cans, juice/milk jugs – cut the bottoms off to create 2-4″ tall cylinders and place them around your growing dahlias. The slugs will have a difficult time getting over that wall. Just be careful not to cut yourself when making these.
  • Have any leftover charcoal from that barbeque that you didn’t invite us to? Just sprinkle some of the charcoal dust from your briquettes around the area that you want to protect from those evil slugs and they will stay the heck away. You can toss a few briquettes into a bag and stomp on them or hammer away – whatever you need to do to get your frustration at the slugs out.
  • If those containers you made aren’t enough – meaning you have some sneaky slugs in your ‘hood – then wrap a piece of duct tape (sticky side out) around that container you have at the base of your plant. That will definitely keep those slugs out.
  • Finished with that newspaper yet? Ready to give up on that crossword? – If you roll up entire sections of newspaper (Our team didn’t win? Great! I mean, Better luck next time, Mariners. Use the Sports section! – it has to be thick) Stick a rubber band around the middle so it will keep its rolled-up shape – then dampen the entire roll and place near your dahlias in the evening. When morning comes, and you head out in your robe (no need for the neighbors to need to see your PJs with puppies and kittens on them, is there?) to get the morning paper so you can try at the next crossword, walk over to where you left the damp roll and pick up the entire thing and toss it into the garbage. Just be careful not to let any slugs and earwigs fall out. Yes, earwigs like damp newspaper, too – though they like crumpled up balls better.

Hope this gives you some ammo to use against those squishy, slimy, just-plain-icky foes!

- The Dahlia Doctor

Dear Dahlia Doctor, My Tubers Are Squishy

Dear Dahlia Doctor,

I stored my tubers in plastic bags with vermiculite in my basement at approximately 43 degrees Fahrenheit.

Why are some tubers squishy and shrunk and others are firm and normal?

Squishy Tuber

Just look at how squishy they are!!

Squishy tuber mysteriously damaged even when stored correctly

How did these get so squishy when they were stored in the correct manner?!

Help me, Dahlia Doctor! What went wrong to make me lose these tubers?! Did I do something wrong when storing them? I followed the common storage methods and they have worked successfully for me in previous years.



Unfor-squished Circumstances


Dear Unfor-squished,
It looks like the tubers that are squishy were put in storage when they were still damp; too much moisture in the packaging will cause rot.  

The ones that are shriveled were probably allowed to dry too long before they were stored.  It also happens that some tubers that are narrow and/or flat will not keep because they dehydrate from the storage in dry vermiculite.  

After cutting, the tubers should only be allowed to stand before packaging and storing for a few hours. During that period the outer skin and necks will dry sufficiently for storage.  Thicker/larger tubers will retain a little more moisture and tend to rot when stored in plastic or saran wrap if not properly dried before storage.  

Tubers should always be checked a couple of times during the storage period. With regular inspection, tubers that are starting to rot can be discarded and will not spread rot to other tubers within the storage container. 

- The Dahlia Doctor

Deer! Dahlia Doctor

Dear Dahlia Doctor,

HELP! I have deer running all over my property! They’re in my dahlias! Do you know of anything I can do to stop them from coming!?!

Undeer Siege


Dear Undeer Siege,

Those pesky deer get into everything, don’t they? I have some possibly solutions you can try on your property to see if it will help keep them away.

  • If you have any old shoes – the stinkier the better – toss them around the edge of your garden. Hopefully the smell of humans will keep them from approaching
  • Did you know deer don’t like to walk on Bubble Wrap?! They just won’t do it! Place some sheets of Bubble Wrap along the edges of your garden and use something heavy like rocks to weigh it down.

Hope that helps keep Bambi away!

- The Dahlia Doctor

Dear Dahlia Doctor, I Think I Just Killed My Dahlia Before It Had A Chance To Live

Or, cut the dahlia stalk close to the ground at the end of the previous growing season… but if you do that, and are like me with a very unorganized garden, you may fear forgetting where you planted your dahlia and then not being there when it first pops out of the ground and then losing it to those dastardly slugs! *shakes fist at evil slugs & snails that never go away*


Don’t pull this dead dahlia stem/stalk out. Cut it instead, as close to the ground as you can when you see new dahlias growing. By the way, this plastic around my dahlia is from an orange juice jug; I use cut up milk jugs and juice jugs to form a wall between my delicate dahlias and heinous slugs.

So… somehow there came a thought that doing this was a good idea since some new dahlias have begun to pop up here and there and doing this would make more room for them.

Oops. This one is still among the living.

Yeah… NO!

Apparently, the part that is below ground can still be alive. Well, nobody ever explained that… and there may be many others out there who may find themselves in the same situation.

As you can see, the inside is very much alive.


Is there a chance for my dahlia? I pulled out the dead (what I thought was dead) stem and ended up pulling out part of the living plant… oops… it had new shoots growing from it. If it gets planted, can it survive? What should I do?!
Unjustly Framed for Dahlia Murder

We will see if it lives… for now it remains on life support.

Dear Framed,
Dig up the entire clump of that dahlia.  Wash the tubers off with a strong stream of water from the hose then you will undoubtedly see eyes sprouting.  Cut each tuber with an eye and a piece of the main stem, then replant those tubers for more dahlias.
Or see what happens to the section that you broke off and then cut apart the tubers once the growing season is over and store the cut tubers over winter and replant them next year.
Attend one of our meetings for instructions on how to cut tubers. Dahlia experts are always on hand for some one-on-one chats.
- The Dahlia Doctor


Dear Dahlia Doctor, My Leaves Look Funny

Dear Dahlia Doctor,

My leaves are a really funny color… they also have holes in them. Do you have any ideas about what my problem could be? How do I fix it?



Unbe-leaf-able Colors

Dear Unbe-leaf-able,
The holes in the petals are caused by earwigs.  Thats why they come to visit.  To eat. You can use Sluggo to combat the earwigs, refer to the previous post about earwigs to learn more.

As for the leaves, it appears that you might have Red Spider Mites. They make their home on the underside of the leaf, where they puncture the plant’s cells in order to feed. If they build a colony, you will see a very fine webbing on your plants where they lay teeny-tiny eggs. It is possible for a single, mature female spider mite to lay over one million eggs in less than a month. If you can’t get your hands on a commercial-grade spray, a more natural way to go is to use Monterey Natural Mite & Insect Control, which is “effective against all stages of mites and pest insects” and “provides rapid knockdown and residual control of spider mites, whiteflies, aphids, scale, mealybugs, leafhoppers, caterpillars and many more.” There is also Mite-X Spider Mite Killer. One thing to note is that the miticides may not affect the eggs, so your would need to repeat the application of the spray every 10-14 days. Another product to try would be Vegol Year-Round Pesticidal Oil. You could also try Bang! which helps heal leaves that were damaged by spider mites.

Though we are nearing the end of the season, you could still give these a try.

- The Dahlia Doctor



Dear Dahlia Doctor, My Flowers Have Earwigs.

Dear Dahlia Doctor,

I have an earwig problem. What is/are some of the best solutions to preventing earwigs from eating dahlias?

An Earwig Inside Foxy Lady

An Earwig Inside Foxy Lady

Exasperated by Earwigs

Dear Exasperated,

For earwigs you can use Sluggo Plus*.  It’s fairly expensive, but you only use a little.
To use, you just sprinkle it on the ground around the base of the plant. Reapply as the bait is used up or the problem persists.

*A similar product is Sluggo, which is the variety that is safe for your pets to be around, but it doesn’t offer the same protection against earwigs, but is great for snails and slugs. If you are worried about the safety of your animals, you could also try Safety Brand 3-in-1 Garden Spray, or Safety Brand Ant & Crawling Insect Killer.

Good luck in your battle against earwigs!
- The Dahlia Doctor