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