Originating in Mexico and then brought into Western Europe more than 200 years ago the Dahlia is one of the more popular summer flowers.
Through years of hybridizing there are so many different flower types, colours, and sizes that there is one to fit any landscape. They look beautiful planted in the flowerbed, as well as make great container plants.
Dahlias can be grown from seed, but is usually grown from tubers, which will give you faster, larger plants. Tubers are available in the spring and are now at the garden centre.
It’s too early to plant them outdoors, but to get a head start on the season, plant the tubers in containers indoors now, so that the plants will start to grow and then in late May after all risk of frost has passed the plants can be planted outdoors. The easiest way to start them indoors is to plant the tuber in a peat pot, that is large enough for the tuber to fit in comfortably. Use a good quality potting soil to fill the pot. When placing the tuber in the peat pot, make sure that the top of the tuber is just above the soil surface. After it has been planted, give it a thorough water, and the place it in a warm sunny location, such as a south facing window. Let the soil go slightly dry between each watering, as you do not want the tuber to rot due to too much moisture. When you begin to see new growth, fertilize the tuber with a plant starter fertilizer such as 10-52-10 which will give the tuber a good system. After a couple of applications of 10-52-10, switch to an all purpose fertilizer such as 20-20-20. To produce a compact full plant, pinch out the centre of the plant after it has formed three sets of leaves which will cause it to branch out.
A couple of weeks before you are ready to set the plant outdoors (beginning of May) harden off the plant by placing it outdoors during the day and bringing it indoors at night. This will get the plant acclimatized to the outdoor weather. Do not get too anxious when it is time to place the plant outdoors, as Dahlias have very poor frost tolerance. It is better to wait and make sure that there is no threat of frost.
When planting outdoors, choose a sunny location, but avoid hot midday heat. Keep them evenly watered not allowing it to go too dry, but also do not keep it too wet. Fertilize weekly with a flowering plant fertilizer such as 12-36-12. To keep plant producing flowers, remove the old finished flowers as they appear so that the plants energy will go towards producing new flowers. Removing the old flowers will also keep the plant healthy and looking good.
Dahlia tubers are not hardy and so need to be dug up for the winter if you want to save them year to year. Dig up the tubers in the fall after the first killing frost has blackened the plants foliage. Cut the foliage back to 15 cm from the tuber and carefully dig the tuber out shaking off any excess soil. The one tuber that was planted in the spring will have multiplied to a few tubers, so try to keep them all intact as one plant. Allow it to air dry for a few hours outside in the sun before bringing it indoors. Its important to allow the moisture to drain out from the neck, and this is done by placing the tuber upside down for a few weeks in an area that is above freezing and airy. When the neck of the stem is dry, the tuber is ready to store. Label the tuber with name, size, colour etc. And then place it in a container that is filled with vermiculite, dry sand or peat moss. Store it where the temperature is 5-8 Celsius. Check the tuber every few weeks to see if it is healthy with no signs of rot. If there is rot, remove the infected area immediately to prevent it from spreading.
You also want to check to make sure that the tuber does not become too dry. If it becomes too dry, take it out of the container and mist it with a minimal amount of water and then put it back in storage. Tubers should be taken out of storage in March, which is when they can be divided and then replanted. When dividing tubers, use a clean, sharp knife and ensure that each tuber has at least one eye.
Saving the tubers and dividing them, makes Dahlias not only an attractive flowering plant but also an economical one!
Jos Van Hage owns and operates two Art Knapp Home and Garden Centres in Prince George:
- Highway 16 West at Kimball Road
- Highway 97 North at Northwood Pulpmill Road ( opening on April 1st for the season!)