A Trip to the Dahlia Farm...

By Amy Lentz, Weld County CSU Extension  - Horticulture

It's that time of year when many of our garden's flowers start to putter out or look kind of drab. But the end of the summer is when the dahlias shine! Two weeks ago, a small group of CSU Extension folks took a tour of Arrowhead Dahlias, a family owned and operated dahlia farm located in Platteville, a small town in Weld County. It was a beautiful morning with good weather and lots of ooh's and aah's as we meandered through the many hoop houses filled with dahlias of all colors and sizes.

Arrowhead Dahlia farm in Platteville, CO

Arrowhead Dahlias was established in 2000 by Calvin and Julie Cook and specializes in growing a wide range of dahlias, along with a smaller crop of other popular cut flowers like lisianthus, zinnias and sunflowers. But their main attraction...the dahlias!

Some of the many, long hoop houses filled with dahlias!

Another popular cut flower grown - Lisianthus

The three-acre farm is filled to the brim with over 200 different dahlia cultivars, many in full bloom for us to admire while we toured the long hoop houses. The structures were covered with a light shade-type covering used to protect the flowers from hail storms that can be common in the area. They have approximately 12,000 plants in the ground and harvest often to keep the product at peak freshness to send to market. Here are a few of my favorites seen on the tour:

Cornel Bronze

Julio

Karma Chocolate

A view from inside the hoop houses

Dahlias find a very favorable climate in Colorado that allows them to grow large, showy flowers. However, they must be grown like an annual since they are not hardy here. They grow as tubers and can be planted much like tulips, but the seasons are switched. With dahlias, you would dig them up in the fall and plant the tubers in the late spring after any chance of frost has past. They don't need a lot of extra care right after planting, just wait until they sprout above the soil then start them on regular irrigation. A drip line set with an automatic watering system or timer can help to keep the dahlias watered on a regular basis as they don't like to dry out. Dahlias prefer a sunny location with plenty of room to grow. You can also grow them in containers, but make sure to give them a larger pot and staking so they don't flop or blow over - they can get quite large and tall, depending on the cultivar. For more information on planting dahlias in Colorado, check out the Plantalk article from CSU, HERE.

Calvin cutting a dahlia at the ideal stage to send to market

There are over 15,000 florists in the US, and about 70% of the retail flowers sold in the US are imported from Colombia. Other big players on the cut flower scene are the Netherlands and Ecuador. Although the US doesn't even make it into the top 10 for countries with the most exports of cut flowers, the local Colorado-grown cut flower scene is vibrant and growers like Arrowhead Dahlias offer a local product that doesn't have to board an airplane or cargo ship to make it into your bouquet. Check with your local farmers market to find cut flower growers near you!

To learn more about dahlias and other spring-planted bulbs, corms and roots, check out CSU's fact sheet, HERE.

Totally Tuber: Planting dahlias in your garden

Posted by: Alison O'Connor, Larimer County Extension

I'm stepping up my game this year at the Larimer County Fair. I've entered nearly every year since I started working for Extension and love the competition, the judges' remarks and the sheer chaos of entry day. But I've never entered much in the Open Class Flower Show, primarily because I don't feel my flowers are worthy. Insect damage, bleached petals and misshapen foliage does not make the cut in our judge's eyes. Plus, there are really, really good flower growers and they actually know what they're doing.

But this year I bought dahlias. I grew a few several years ago and they were surprisingly easy, low-maintenance plants. But I had tucked them in a bed on the side of the house and didn't enjoy them much. Then I got an email from an Oregon dahlia company..."Sale! 50% off! Buy dahlias now!" So I did.

For those who haven't attempted the "summer-blooming bulbs", here's a quick lesson in planting dahlias. Don't be scared--they're really no different than a daffodil or tulip. Yes, they do need to be dug from the ground in fall (they are not winter hardy in Colorado), but properly stored and cared for, dahlias (and their folk) can last for years.

I purchased a mix of flowers from the "Cut Flower Collection" and also a group from the "Itsy Bitsy Collection". I figure that by the time the Fair rolls around, I should have enough flowers to scrape together an arrangement. And the names are the best part! Some of my cultivars include 'Bride to Be', 'Lights Out', 'Bambino' and 'Angels of 7A'.

Each tuber comes stamped with the variety name.

First of all, read the instructions sent by the grower. They know what they're doing and what's best for their plants. One of my favorite things about dahlias is that they don't need to be watered following planting--only after sprouts appear above the soil surface.

Planting instructions attached to the dahlias.

Carefully inspect your tubers and make sure they are firm without any signs of rot. If they have sprouted, you can snip back the new growth to a length of one inch. This will not hurt the dahlias and will actually encourage better growth.

Cut back new growth to 1" in length.

I have a sunny location in my garden where all the plants died over the winter (except for the silver lace vine, which nothing can kill). A perfect location for the dahlias. I raked back the mulch, squealed at the amount of worms I found and started digging. Dahlias need to be planted flat on their side 6" deep and 18-24" apart. The plants can get quite large at maturity (anywhere from 12" to 5+ feet; taller plants will need staking) so proper spacing is necessary.

Pulling back the mulch to expose the soil.

Plant dahlias flat on their side in a 6" deep hole. Space tubers 18-24" apart.

Digging each hole was getting cumbersome, so I stepped up production and dug a trench and placed the tubers, properly spaced, in the trench.

The dahlias are planted and ready to cover with soil.

Now, because I always forget where I plant my bulbs, I decided to mark where they were planted with a golf tee. (Of which I have many on hand.)

Handy dandy golf tees to mark where the tubers were planted.

We have a new addition to our household, Maple. She is a rescued research beagle from Colorado State University and she is ALL PUPPY. Curious about everything and learns something new about the world every day. I didn't realize she would have such an interest in the dahlia tubers. I should have known. Now I'm worried that she may be inclined to dig them up, so I bought some fencing.

Maple meeting a tuber for the first time.

I covered all the tubers with soil, added mulch (in a thin layer) across the planting areas and marked each one with a golf tee. Now I just have to wait a few weeks for growth. Let's hope it stops raining.

And if you don't have garden space, dahlias can easily be grown in containers. Just follow the same spacing and depth requirements mentioned above. Also consider the mature size of the plant and your container size--ensure it's big enough to support the plant at maturity (generally a 12" by 12" container will be large enough). Cover the tuber with a few inches of soil and water it in. Be careful about watering until growth starts...but don't let the potting media dry out. Also make sure your media is well drained so the tubers don't rot. You'll also need to fertilize throughout the summer.

Dahlias are great container flowers. Just make sure your container is large enough to support the plant when full grown.

Later this fall, I'll be sure to post about what to do to harvest and keep your dahlias for next year. I'm sure Maple will be a great helper. For the official CSU Extension Fact Sheet on summer-blooming bulbs, click here.

Maple requested the pansies.
I'll remove them as the weather gets too hot and just allow the dahlia to grow.