Dahlia “Dos”, Dahlia “Don’ts”

By Tony Filmer 

Flowers, like celebrities, can have cyclical popularity. Based on the volume of customer questions dahlias are the smokin’ hot plant right now. Don’t know them? Check them out at your local garden center and be prepared to be dazzled.

Hybridizers have expanded the range of flower and plant sizes, colors and flower forms to capture the fancy of anyone that likes flowers.  It’s pretty darned cool to watch a quarter sized bud open into an 8” (or larger) flower later in the summer!  Yep, I’m showing my favoritism for the gargantuan dinnerplate types.

I’d love to share a few of the things I’ve learned over the decades I’ve been growing them.

• The smaller bedding dahlias can be grown from seed, but the large-flowered varieties are grown from tubers (potato-like storage organs). They are most often sold as undivided clumps with multiple tubers. Don’t just dig a hole and plop the old clump back in the ground. Get a sharp knife and cut a tuber from the mother clump. Each tuber must have an eye, or bud, to grow a new plant. Eyes will be at the end of the neck of the tuber, coming from last year’s stem. A dahlia clump might have as few as one, or as many as three or four eyes. 
• Like tomatoes, nothing is gained by planting dahlias too early. Dahlias are tropical in origin and shouldn’t be planted until soil temperatures are consistently above 60°F. They abhor cold, wet soils.
• Dig a hole 4-6” deep. The tuber will be placed horizontally in the bottom of the hole. Life is easier when you place the stake (you will need a stake for these big, vigorous ) in the hole next to the eye of the tuber. Dahlias, like vampires, resent having a stake driven through their heart, which is the tuber!