Let’s Grow Dahlias

Jen’s Garden- A Mix of Flowers and Veggies

If you’re going to grow one flower this year, we want you to experience growing dahlias. This blog post will provide you with everything you need to know in a condensed, cliff’s notes ‘Garden Girls’ version.  

How To Get Big Blooms?

Dahlias are grown from tubers or transplants and are planted in the spring.  They need full sunlight and warm soil to grow.  February - early April are ideal times to plant dahlias here in Houston. 

The bigger the bloom, the more sensitive to heat the dahlia will be. When temperatures hit 90 degrees, they will likely stop blooming.  What does this mean for us?  It means that we can enjoy spring flowers, but we’ll likely need to provide shade for blooming dahlias once May hits. Dahlias do best with light afternoon shade (use a shade cloth or beach umbrella to protect these beauties).

The more you feed dahlias, the more they’ll produce.  Leaf mold or mushroom compost mixed in with sandy loam soil will offer the best results in prolific blooms.  You can also include a fertilizer low in nitrogen and high in phosphorus every week or two.  The phosphorus is responsible for the showy petals.

Deadhead after blooms begin to fade to encourage new growth, using sharp clippers. You can pinch the flower top after you see three sets of branches appear to force new growth. 

Common Issues When Growing Dahlias

Drip irrigation is preferred for dahlias, as it is the gold standard for all raised bed plantings.  Dahlias are susceptible to stem rot and powdery mildew and for those reasons, we recommend watering in the morning, at soil level, so plants have adequate time to dry.  

Slugs, aphids, spider mites, and caterpillars are common pests attracted to dahlias. The best defense for pest pressure is a good offense, so spend time checking on your plants (all of them!).  Ladybugs are my number one choice for controlling aphids. Release them under the plant in the evening. You can purchase a container of ladybugs at a local nursery.  

Garden Girls’ Favorite Dahlia Varieties

Our favorite varieties include the decorative, ball, and pompom types. Cactus dahlia, Cornel dahlia, and Cafe au lait are ideal choices for cut flower gardens.

We hope you will leave space in your garden to grow Dahlias this year. They can be a showstopper in spring.