How to Care For Dahlias

Welcome back to part 2 of my dahlia tutorial! For part 1 go here:

How To Plant Dahlias

Probably about now (July), you’re looking at a whole lot of green in your dahlia bed. Maybe a few blooms but basically you’re on pins and needles waiting for the flower explosion to happen. Trust me, it’s coming! So I figured now would be a great time to share some tips on how to keep your dahlias blooming and happy until the fall frost rolls in. 

Cutting Flowers

Cut flowers often! What you need to understand about flowers in general is that when you cut a bloom, you’re rerouting the plants energy to other buds causing more blooms to happen. So the more dahlias you cut, the more the blooms you’ll get! When cutting flowers ideally you want to cut them in the morning when it’s still cool outdoors. Cut the stem where it connects with more flower stems. this method is great for vase flowers. If you’re creating a bouquet, you can go down even further to the first set of leaf nodes for a longer stem. Also remember to deadhead any spent flowers, again, this will reroute the plants energy to new blooms.

Here Come the Clowns

Pinching or Topping your dahlias

I was really scared to do this the first time. I mean, who cuts their plants mid growth?? Surely this can’t be good for the plant! So last year, I held my breath and did it. A few weeks later I had fuller, bushier dahlias that produced more flowers! So yes, pinch your plants! Rather than describe it, here’s a super useful video from Swan Island Dahlias in Oregon.

Staking and tying  

Most dahlias will need a little support as they grow. If you like big flowers, be ready for big plants! As you can see in this picture at my old house, most of my plants are 4-5 feet tall. With all those flowers at the top, they need support! My current dahlia bed is next to a 3 foot fence so I use twine to tie up the tall ones once they look like they need support. For the bed you’re looking at in this picture, behind each plant is a five foot hardwood stake that was hammered into the ground when they were planted. Again, one they get too tall, grab some twine and loosely connect the stalks to something sturdy for extra support. 



Dahlia are not very demanding plants. Remember, they are native to the mountainous regions of Mexico so they’re used to extremes in weather and sporadic watering. Here’s my basic watering breakdown for the summer months with little to no rain:

70-80 degrees – water every 3-4 days

80-95 degrees – water every other day

95+ – water every day

I always water them in the evening with a garden hose. 5 seconds per plant seems to be the perfect amount. 


I approach fertilizing dahlias the same way I fertilize my whole garden: once a week with a water solvent fertilizer like Miracle Grow. Again, they don’t need much and often I’ll even forget this step and still have tons of blooms! 


Image result for corrys deadlineSuch big plants and such pretty flowers are naturally going to attract some visitors that you don’t want coming in and ruining all your fun. Slugs are a big one. They love dahlias! Over the years, I’ve tried to ward them off using several natural approaches but I’ll be honest with you, they don’t work consistently. Your best bet is to go get some good old-fashioned slug bait. I prefer the liquid kind like Corry’s Deadline, simply make a border around your bed and your plants will be safe.

The other one to be vigilant of is spider mites. 


I had a run in with these teeny tiny spider-like critters one very hot summer several years ago. The above picture is what it looks like up close. If you dahlia starts to look like the picture below, get a closer look, you may have spider mites. 


Fortunately, the solution is simple. They’re so tiny and fragile, a good spray of water a couple of times a day will get rid of them and save the plant. 


Here’s the same plant a week later with new growth coming in. 


Well I’ think that about covers it! You’ should be good to go with your dahlias until it’s time to put them away to winter around October or November. Be expecting my next post around then! Cheers!

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About Malia

Hi There! My name is Malia. I love to cook, garden, fish, and live in a small town in the Pacific Northwest. Come join in my silly adventures as I tromp through the garden, cook up a storm, and try to live every day to its fullest!

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