It’s exciting when you find a plant that gives you joy and feeds our pollinators so well. This past growing season I stumbled across a flower that is gorgeous, easy to grow, has tremendous variety, and feeds the pollinators. Dahlias!
Dahlias had escaped my attention until this past growing season. I’m not sure why. One reason may be that dahlias are not on pollinator flower lists. But last winter I picked up a copy of Cut Flower Garden by Erin Benzakein. She is founder of Floret Flower Farm and a leader in the flower farmer movement. Her book is beautiful and she captured my attention. The dahlias are gorgeous, sophisticated, and come in an amazing range of colors.
I dived in. I ordered over 50 varieties, tore up some lawn (yippee!), planted some tubers, and was rewarded by an amazing crop of cut flowers. They were so productive that I ended up selling bouquets at a local farm.
I realized that the right dahlia can feed a bee or a butterfly. In fact, the pollinators seem to love dahlias and even prefer them over other bee-flowers. And dahlias bloom from late summer through the entire fall season–at a time when bees need nourishment. Yet dahlias aren’t commonly listed on pollinator flower lists. Let’s reconsider! Here is my advice on how to grow them and which ones to plant for the bees.
Which Dahlias Feed the Bees and Butterflies?
There are thousands of dahlia varieties to choose from. Many simply have too many petals for the pollinators to access the pollen and nectar found in the center of the flower. (Perhaps this is why dahlias are generally not listed as a pollinator flower.) But the open-centered dahlias do a great job of feeding the pollinators. Allow me to run through a few.
Dahlias classified as singles, collarettes, and anenomes should feed the pollinators well. The center of the flower is open and visible once the flower blooms. Some examples are Totally Tangerine, Apple Blossom, Waltzing Mathilda, and Dad’s Favorite. (See the pictures below.)
Dad’s Favorite (lower left above) turned out to be a butterfly magnet and was especially loved by the Monarch butterflies. They even ignored the butterfly bushes (Buddleia) in my yard and went straight to this dahlia. So fun to watch. This anenome type flower has a large cluster of tubular florets in the center of the flower, with simple petals surrounding it. These tubular florets seemed to be made for a butterfly’s proboscis to extend into and drink up the nectar. I saw bumblebees also feeding off this flower, while the honeybees did not. I am guessing this is because honeybees have a short tongue, whereas bumblebees have a long tongue.
There are also other varieties that initially bloom with lots of petals, but after a few days, the button center opens up and the bees can feast. Some examples of these are Golden Sceptor, Daisy Duke, and Preference.
Are Dahlias Hard to Grow?
Dahlias are easy to grow. And they can be grown organically with great success. But they do have a few “rules” that the gardener needs to learn. Here are some highlights:
- Dahlias are typically grown from tubers. (To grow them from seeds, see below.) Tubers need to be planted in garden beds once the soil has warmed up to 55 degrees. In my zone 5 garden, that means late May, usually around the same time you plant tomatoes.
- Consider adding a few inches of compost to the planting area to feed the beneficial micro and macro-organisms in your soil and generally improve soil quality.
- If a soil test has shown that you need to add amendments to your soil, choose an organic fertilizer that is lower in nitrogen. (Too much nitrogen and you may get more foliage and less blooms.)
- Plant the tuber 4-6 inches deep, on its side.
- Do not initially water the tuber, otherwise it may rot.
- Once growth appears above the soil surface, you may water.
- Most dahlias require staking. At planting time add a strong stake or post next to where you planted the tuber. If you don’t want to stake, consider choosing a shorter bedding dahlia that won’t require staking.
- Dahlias are thirsty flowers. All of those gorgeous petals require water. Unless it has rained, plan on watering them deeply 2-3 times a week.
- Once the dahlia has started growing and days are consistently warm, I recommend adding a mulch to help conserve water.
- For maximum number of stems, pinch the center top leaves off when plants are about 12″ tall.
- Dahlias can be grown as a perennial in Zones 7 and higher. In zones 6 and lower, you will need to dig up and store the tubers in the Fall.
Growing Dahlias from Seed
With enough time, you can also grow dahlias from seed. Start seeds indoor 8-10 weeks before your last frost date. They should bloom the same season. Keep in mind you will see a variety of colors and forms. If there is a particular blossom that you (and the bees) like, then you can save the plant’s tubers for the next growing season. Dahliaaddict.com can be a great resource on where to find a variety and provides a supplier list. Have fun browsing!
Are you growing dahlias? Share with readers which varieties the bees and butterflies love.