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, 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, 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