A Step-by-Step Guide for Growing Dahlias

Author: Saiqa Najeeb
Last Updated On: July 5, 2023

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Are you ready to witness nature’s paintbrush at its finest? Can you envision a garden bursting with vibrant colors and exquisite blooms, each petal a masterpiece? Now, take a moment to imagine the sheer joy and pride of cultivating such a spectacle in your very own backyard. It’s not only possible but within your reach!

This guide will unlock the secrets to growing dahlias – enchanting flowers that can transform your garden into a living canvas. So, let’s embark on this botanical adventure together and explore the wonders of growing dahlias, where every day feels like stepping into an art gallery of nature’s most stunning creations.

About Dahlias

Dahlias, often called the “Queens of the Garden,” are a mesmerizing genus of flowering plants belonging to the Asteraceae family. Native to the highlands of Mexico and Central America, these enchanting blooms have gained immense popularity among gardeners worldwide for their stunning variety of colors, shapes, and sizes.

Dahlias are warm-season plants, so it’s important to wait until the danger of frost has passed before planting them. In most regions, this means planting dahlias in the spring after the soil has warmed up and all frost risks have subsided. Plant them when the soil temperature reaches around 60°F (15.5°C) or higher. Depending on your location, this is typically around late April to early June

Why Should You Start Growing Dahlias Now?

- Spectacular Blooms: Dahlias offer an unparalleled display of blooms in various captivating colors, ranging from vibrant reds, oranges, and pinks to soothing pastels and elegant whites. Their intricate and diverse petal formations, including single, double, cactus, and pompom varieties, make them an absolute visual delight.
- Versatility in Design: With their striking beauty, dahlias make exceptional cut flowers, adding elegance to bouquets and floral arrangements. They also serve as showstoppers in garden beds, borders, and containers, providing a dramatic focal point transforming your outdoor space.
- Extended Blooming Season: One of the remarkable qualities of dahlias is their prolonged blooming period, which typically spans from mid-summer through early fall. This means you can enjoy their captivating blooms and vibrant colors for an extended period, bringing continuous joy and beauty to your garden.
- Abundance of Varieties: Dahlias offer an extraordinary range of varieties to suit every gardener’s preferences. There’s a dahlia for every space and style, from small, compact varieties perfect for containers to tall, majestic cultivars that make a statement in garden beds.

Read our comprehensive guide on Flower gardening 101.

Discover the Varieties of Dahlias

Here are some varietiesthat you can consider for growing dahlias:

Decorative Dahlias: These are classic dahlias with large, fully double blooms that come in a wide range of colors, from bright and bold to soft and subtle.
Cactus Dahlias: Known for their unique and spiky petal formations, they add a touch of whimsy to any garden.
Anemone Dahlias: With a distinctive appearance reminiscent of anemone flowers, these dahlias feature a central dome Bayou’ with its mesmerizing purple and white blooms.

Where Should You Plant Dahlias?

Dahlias thrive in locations that receive full sun for at least 6 to 8 hours daily. Find a spot in your garden that offers ample sunlight and good air circulation. Ensure the area has well-draining soil to prevent waterlogging, as dahlias prefer moist but not waterlogged conditions. It’s also beneficial to provide some protection from strong winds, as their tall stems can be susceptible to damage.

How to Prepare Your Soil for Growing Dahlias?

Preparing the soil properly is essential for promoting healthy growth and abundant blooms. Here’s how to prepare your soil for dahlias:

Clear the Area: Remove any weeds, rocks, or debris from the planting area. This will minimize competition for nutrients and create a clean space for your dahlias to thrive.
Loosen the Soil: Use a garden fork or tiller to loosen the soil to a depth of around 12 inches (30 cm). This helps improve drainage, aeration, and root penetration.
Amend the Soil: Incorporate organic matter into the soil, such as well-rotted compost or aged manure. This enriches the soil with nutrients, improves its structure, and enhances water retention.
Test Soil pH: Dahlias prefer slightly acidic to neutral soil with a pH between 6.0 and 7.0. Test your soil’s pH using a soil testing kit, and if necessary, make adjustments by adding soil.

Check out how to choose the best soil for your vegetable garden.

Step-by-Step Guide for Planting Dahlias

1 Method 1: Planting Dahlia Tubers in the Ground

Here is how you can plant Dahlia tubers in the ground whilw growing dahlias:

Choose Healthy Tubers: Select high-quality dahlia tubers from a reputable source. Look for firm, plump tubers without any signs of rot or damage.
Timing and Site Selection: Wait until all frost risks have passed and the soil has warmed up. Select a sunny location with well-draining soil and good air circulation.
Prepare the Soil: Clear the planting area of weeds, rocks, and debris. Loosen the soil to a depth of 12 inches (30 cm) using a garden fork or tiller. Incorporate organic matter into the soil, such as compost or aged manure.
Dig Planting Holes: Dig holes about 6 to 8 inches (15 to 20 cm) deep and wide enough to accommodate the tubers.
Place and Position the Tubers: Lay the tubers horizontally in the planting holes with the eye buds facing up. Position the tubers about 18 inches (45 cm) apart to allow sufficient space for growth.
Cover and Water: Gently cover the tubers with soil, ensuring they are completely covered but not buried too deeply. Water the planting area thoroughly to settle the soil and initiate growth.

2 Method 2: Planting Dahlias in Containers

Here’s a step-by-step guide for planting dahlias in the containers:

Container Selection: Choose a container with a diameter of 12 to 18 inches (30 to 45 cm) and a depth of 12 inches (30 cm). Ensure the container has drainage holes at the bottom.
Fill the Container: Fill the container with a well-draining potting mix, leaving about 2 inches (5 cm) of space from the top.
Place the Tubers: Lay the dahlia tubers horizontally on the soil surface, positioning them with the eye buds facing up.
Cover with Soil: Gently cover the tubers with additional potting mix, ensuring they are completely covered but not buried too deeply.
Watering: Thoroughly water the container, allowing the excess water to drain from the bottom.
Positioning: Place the container in a sunny location that receives at least 6 to 8 hours of direct sunlight daily.

Check out our guide on container gardening 101.

How to Care for Growing Dahlias?

Watering: Water deeply and regularly to keep the soil moist but not waterlogged. Aim for 1 to 2 inches (2.5 to 5 cm) of water per week, especially during dry periods. Water at the base of the plants to avoid wetting the foliage, as wet leaves can lead to fungal diseases.

Mulching: Apply a layer of organic mulch, such as straw or shredded bark, around the base of the plants. Mulching helps retain soil moisture, suppresses weeds, and regulates soil temperature.

Fertilizing: Feed dahlias with a balanced, water-soluble fertilizer every 4 to 6 weeks during the growing season. Look for fertilizers with a higher middle number (phosphorus) to promote flower production. Follow the package instructions for proper application rates.

Stake and Support: Tall dahlia varieties may require staking or support to prevent the stems from bending or breaking. Install stakes or cages early in the growing season to avoid damaging the root system. Secure the plants to the support structure using soft ties or clips.

Deadheading: Regularly remove spent flowers by cutting them back to the nearest set of healthy leaves or buds. Deadheading encourages continuous blooming and redirects energy into producing new blooms.

Winter Protection: Dahlias are not cold-hardy in most regions, so protecting the tubers during winter is important. In autumn, carefully dig up the tubers after the foliage has been killed by frost. Remove excess soil, allow them to dry for a few days, and store them in a cool, dry location. Store tubers in containers filled with dry peat moss, vermiculite, or sawdust to prevent drying out.

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Common Pests and Diseases to Watch out for Growing Dahlias

Dahlias are not very hardy but can still be susceptible to certain pests and diseases. Here are some specific pests and diseases that can affect dahlias:

Aphids:

Aphids are small, soft-bodied insects that cluster on the undersides of leaves and suck sap from the plant.
They can cause distorted growth, yellowing leaves, and the presence of sticky honeydew.
Use insecticidal soaps, neem oil, or a strong stream of water to control aphid infestations.

Slugs and Snails:

Slugs and snails are common garden pests that feed on the foliage of dahlias, leaving behind irregular holes and slime trails.
They are most active during damp and cool conditions.
Remove hiding spots, such as debris and boards, and use organic slug and snail baits or traps to control them.

Powdery Mildew:

Powdery mildew is a fungal disease that appears as a white or gray powdery coating on the leaves, stems, and flowers.It can weaken the plant and inhibit growth.
Improve air circulation, avoid overhead watering, and apply fungicidal sprays specifically labeled for powdery mildew control.

Botrytis Blight (Gray Mold):

Botrytis blight is a fungal disease that causes brown spots, wilting, and decay on dahlias’ flowers, stems, and foliage. Cool, humid conditions favor it.
Remove affected plant parts, improve air circulation, and apply fungicides labeled for botrytis control.

How Long Does it Take for Growing Dahlias?

The duration of growing dahlias can vary depending on the planting method and specific cultivar. However a general expected duration for growing dahlias is given:

Planting to Germination: Dahlias planted as tubers typically take around 2 to 3 weeks to germinate and emerge.

Flowering Time: After germination, it usually takes approximately 8 to 10 weeks for the plants to start blooming.

Total Growth Cycle: From planting to full blooming, dahlias grown from tubers in the ground can take anywhere from 12 to 16 weeks.

Tips for Harvesting and Storing Dahlias

Harvesting Dahlias:

– Wait until the blooms have fully opened and are at their peak before harvesting dahlias.

– Use sharp, clean garden shears or pruners to cut the flowers, making a clean diagonal cut.

– Cut the stems early in the morning or late in the evening when the plant is well-hydrated.

– Leave a sufficient stem length (around 6 inches) for better handling and arranging.

– Remove any foliage or thorns from the lower part of the stems.

– Immediately place the freshly cut dahlias in a bucket filled with lukewarm water.

– Allow the flowers to hydrate for a few hours, ideally in a cool and dark location.

– Recut the stems underwater before arranging them in a vase or floral arrangement.

Storing Dahlia Tubers:

– In mild winters (USDA hardiness zones 8 and above), dahlias can be left in the ground and covered with a thick layer of mulch for winter protection.

– In colder regions, dahlias must be dug up and stored indoors during winter.

– After the first frost has killed the foliage, carefully dig up the tubers using a garden fork or spade, being cautious not to damage them.

– Gently remove excess soil and allow the tubers to dry for a few days in a well-ventilated area away from direct sunlight.

– Separate clumps and place the tubers in dry peat moss, vermiculite, or sawdust container.

– Store the tubers in a cool, dry location with a temperature range of 40-50°F (4-10°C) to prevent them from drying out or freezing.

To Sum Up

Growing dahlias can be a rewarding and fulfilling experience. Dahlias can add beauty and vibrancy to any garden or a floral arrangement with their stunning blooms and various colors and shapes. By following the proper planting methods, providing adequate care, and taking the necessary steps for harvesting and storing, you can enjoy a successful dahlia garden year after year.

So why not embark on your journey of growing dahlias? Whether you plant them directly in the ground or in containers, dahlias can thrive with a little attention and care. Explore the numerous varieties available, from decorative to cactus, and unleash your creativity with stunning colors.

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