When it comes time to adding colour, form and texture to your window boxes, seasonal planters or garden beds, there are a wide variety of annual plants to choose from! So this week we wanted to tell you a little bit about the easy to grow, vibrant Dahlia! Known to bloom all Summer long, these varietal daisy-like flowers are spiky and flamboyant. Available in a wide spectrum of colours and sizes, Dahlia’s make a striking statement in any composition – be it as a cut flower in an arrangement or to add some diversity to your landscape!
Once you’ve made the choice on the variety of Dahlia that you would like to incorporate into your garden, it’s time to choose the ideal planting location for your annual.
Planting: You don’t want to rush with planting Dahlias, as they will struggle in cold soil. Although you typically wait for a consistent 10°C/50°F ground temperature before planting, you’re safer to aim for 16°C/60°F weather, to ensure there is no danger of a Spring frost negatively affecting your plant.
Note that there are various sizes of Dahlias from dinner plate to petite pom-poms with varying heights and spreads, so be sure to take this into account when adding these flowers to your pot or garden bed.
Sunlight: Dahlias will grow best in a full sun location, meaning they should receive 6-8 hours of direct sunlight- ideally morning light.
Soil: Plant in a well-drained loose soil that is rich and slightly acidic with a pH level of around 6.5 – 7.0, if this type of soil doesn’t sound like your garden, and you have a heavier more clay-like texture, you can simply add in sand and peat moss or manure to lighten the soil for better drainage.
Water: You will want to keep soil evenly moist, watering plants deeply once or twice per week and daily on hot Summer days.
Maintenance: Fertilizing your Dahlias is key to encouraging full floral stems and big leafy plants. The ideal fertilizer for this plant would be high in potassium (third number) and phosphate (second number) and low in nitrogen (first number) to prevent leafy bushes with few blooms. We would recommend using a ½ cup of 5-10-10 water-soluble fertilizer once or twice a month, around the roots of the plant.
Ensure that you keep the growing area free of weeds and deadhead to compel good branching and structure while increasing the chance for new buds. If your Dahlia begins to get top heavy, you will want to add a support structure like a stick or bamboo post to avoid the bloom from bending to the ground and snapping.
With a little research you will discover that Dahlias are considered a tender perennial, meaning they are Winter hardy in specific planting zones (8-11), in Windsor and Essex County we’re gardening in zone 7, which allows us to plant them in the Spring and treat them as annuals or dig them up and store the tubers for the Winter. Add beautiful Dahlia blooms to your plant “must-have” list this year, as you will not be disappointed!