Plant of the Week

This week's plant of the week is "Dahlia"

Picture of Joe Pye WeedDahlia

A member of the Asteraceae family which is related to Sunflowers, Zinnias, Chrysanthemums and Daisies. The form of the Dahlia flower very greatly from small pompom ball type which are 2inches or less in diameter to giant cultivars over 10 inches in diameter.

How to grow Dahlias

Dahlias are easy to grow and yield beautiful blooms from mid-summer through to the first heavy frost. Dahlia tubers are available in most Hardware Store, Garden Centers, Societies and Friends. When obtaining Dahlia tubers, make sure your can see a plant eye similar to those of potatoes. If the tuber does not have an eye or growth point, it is not likely to grow into a strong healthy plant. Put the tuber in a hole several inches deep with the “eye” on the tuber facing up.

Your tubers can go directly into the ground in the spring when the ground has warmed and there is little chance of heavy frost. In our location, plant the tubers the last week in May. If you want blooms as early as possible, you can start the tubers indoors near the end of April. You will then have a small plant ready at planting time. Dahlias can be planted as late as mid-June.

The dahlias will do much better for you when plant them in plain old dirt (PH 6.5 tp 7.0 slightly acidic), even if you think its not the "best" soil, they will be much happier than in purchased soils. Lay the tuber horizontally 4-6” deep, about 18” to 24” apart, and then cover with soil. If the ground is bone dry when you plant, go ahead and water sparingly to get them started. Do not use bark dust or mulch to cover dahlias, as it does not allow the soil to warm up or tubers to sprout properly. This is a good time to apply snail and slug bait to protect the new sprouts.

Most areas have enough rain to fill dahlia water needs until the sprouts appear above the ground. After dahlias are established, a deep watering 2-3 times a week for at least 30-60 minutes with a sprinkler, more required during warmer dryer weather. Hotter climates will need to water more often as conditions require. Proper watering promotes proper blooming. Hand watering is not enough. They love lots of water during the growing season. Water, water, water....

Topping or Pinching
To promote shorter, bushier plants with better cutting stems, pinch or remove the center shoot just above the third set of leaves, this will produce more flower stalk from side shutes and healthier looking plants.

Winter Protection

Store Dahlia tubers indoors for winter protection. Dahlias are not winter hardy in our location. Digging should be done about 2 weeks after a killing frost, the plants will turn brown if frosted hard enough. Tubers dug too early are still “green” and will not store. It is safe to dig by Mid October without a frost. Cut the stalk off to about 4”, gently lift tubers with a spade or pitchfork carefully so as not to break the necks. Wash dirt from the roots and allow to air dry, protected from the elements for about 24 hours them store in a cool dry area which is above freezing.

Pest & Diseases

Dahlias are somewhat susceptible to Snails & Slugs, Spider Mites, Earwigs, Cucumber Beetles, and Mildew (click on each to find more information).