About Dahlias

What are Dahlias?

Dahlias are a type of tuberous plant that belong to the Asteraceae family. Typically, dahlia tubers are planted in late spring, around May, and they usually bloom from July until the first frost hits in autumn. These flowers are great for adding color to border gardens and are also fantastic for cutting. In their native environment, Mexico, dahlias are tender perennials, so if you're in hardiness zone 8 and above, you can leave them in the ground. But if you're in Zones 7 or lower, you'll need to treat them like annuals. Here at our flower farm in southern Manitoba, which is in zone 3, we dig up our dahlias in the fall and store them indoors for the winter.

Dahlias are particularly remarkable due to their diverse forms, which include cactus, peony, anemone, stellar, collarette, waterlily, and dinner-plate varieties, among others. The color spectrum is equally impressive, encompassing nearly every hue except blue.

Planting Dahlias

Make sure to wait until there's no chance of frost before planting your dahlias in the garden. They love 6 to 8 hours of direct sunlight, especially in the morning. Start by digging a hole about 6 to 8 inches deep, place the tuber in with the "eyes" facing up, and cover it with 2 to 3 inches of soil (some say 1 inch is fine too). Avoid watering right after planting to prevent rot; wait until you see sprouts above the soil, then you can start watering. Once established, water them 2 to 3 times a week, and more if it’s really hot and dry.

For spacing, if you're planting large dahlias or those meant for cutting, keep them about 3 feet apart. If you plant them 1 foot apart, they can create a beautiful flowering hedge. Medium to low-height dahlias should be spaced 2 feet apart, while the smaller bedding dahlias or those grown from seed can be planted 9 to 12 inches apart. Just keep in mind that larger blooms, like dinner-plate dahlias, can be quite heavy and may need some support.

For optimal growth, it is recommended to use a low-nitrogen liquid fertilizer.