The ‘Who Dun It’ Dahlia is a captivating flower known for its striking color transformations. This variety stands out due to its unique ability to shift hues, creating an evolving display of color throughout its blooming season. It offers a dynamic focal point in garden beds, containers, or as cut flowers.
Unique Characteristics of ‘Who Dun It’ Dahlia
The ‘Who Dun It’ Dahlia is renowned for its fascinating color transition. Blooms emerge bright white, then develop splashes of cool-toned pink-purple, lilac, mauve, and lavender-blue. This color change can intensify with temperature, light exposure, and bloom maturity. Mature blooms are large, often “dinnerplate” size, measuring 7 to 12 inches wide.
This dahlia exhibits a decorative or informal decorative form, with fully double blooms and somewhat haphazardly arranged petals. The plant is sturdy and vigorous, reaching 36 to 48 inches (90 to 120 cm) tall, making it suitable for garden borders and mixed beds.
Planting ‘Who Dun It’ Dahlia
Site Selection
These plants thrive in full sun, requiring six to eight hours of direct sunlight daily for abundant blooming. Morning sun helps dry dew from leaves, reducing disease. Choose a site with some protection from strong winds to prevent damage to tall stems and large blooms.
Soil Preparation
‘Who Dun It’ Dahlias perform best in well-drained, fertile soil rich in organic matter. An ideal soil pH ranges between 6.5 and 7.0. If your soil is heavy clay or drains poorly, amend it with compost, well-rotted manure, or fine gravel to improve drainage and aeration. Loosen the soil to 10 to 12 inches (25-30 cm) deep before planting for robust root development and better drainage.
Planting Tubers
Dahlia tubers should be planted outdoors after all danger of frost has passed and the soil has warmed (55-60°F / 12-15°C). Dig a hole 4 to 6 inches (10-15 cm) deep for each tuber, placing it horizontally with the “eye” or growth point facing upward. If the eye is not visible, lay the tuber on its side. Space tubers 18 to 24 inches (45-60 cm) apart for air circulation and growth. After planting, water very lightly, or not at all, until the first green shoots emerge, as overwatering before sprouting can lead to tuber rot.
Ongoing Care for ‘Who Dun It’ Dahlia
Watering
Consistent, deep watering is important for ‘Who Dun It’ Dahlias, especially during dry spells. Once established and actively growing, provide one deep soak per week, ensuring the soil remains moist but not waterlogged. Overwatering can lead to root rot, while underwatering can cause wilting and yellowing leaves. Drip irrigation or soaker hoses are recommended to deliver water directly to the root zone, minimizing foliage moisture and preventing disease.
Fertilizing
Dahlias are heavy feeders and benefit from regular fertilization. Once established, fertilize monthly with a balanced or low-nitrogen fertilizer (e.g., 5-10-10) to encourage strong bloom production over leafy growth. Avoid high-nitrogen fertilizers once blooming begins, as this can result in lush foliage but fewer flowers. A single annual fertilization can also be effective if a slow-release product is chosen.
Pest and Disease Management
Dahlias can attract various pests, including aphids, slugs, earwigs, and spider mites. Regularly inspect plants for signs of infestation and address issues promptly. Common diseases include powdery mildew and botrytis, appearing as white coatings or brown spots on leaves and flowers, especially in humid conditions. Good air circulation, via proper spacing and occasional pruning of lower leaves, helps prevent fungal issues. Removing affected plant parts and consistent watering can mitigate many problems.
Deadheading
Deadheading is an important practice for ‘Who Dun It’ Dahlias. It encourages the plant to produce more flowers throughout the season by preventing seed production. To deadhead, cut the spent flower stem back to a leaf or a side branch with a new bud. This maintains plant vigor and extends the blooming period until the first frost.
Winter Care and Tuber Storage
In regions with cold winters (USDA Zones 3-8), ‘Who Dun It’ Dahlia tubers are not hardy and must be dug up and stored indoors. After the first hard frost blackens the foliage, cut stems to 2 to 4 inches (5-10 cm) above ground. Carefully dig up tubers, avoiding damage, and allow them to dry for a few days in a frost-free location away from direct sunlight.
Once dried, gently remove excess soil and trim fine roots. Store tubers in a ventilated container with a slightly moistened medium like peat moss, vermiculite, or wood shavings. The storage location should be cool, dark, and dry, between 35-50°F (2-10°C), to prevent rot or desiccation. Periodically check tubers throughout winter, misting lightly if shriveled or trimming away rotting portions. Labeling each clump helps identify the variety for the next planting season.
Troubleshooting Common ‘Who Dun It’ Dahlia Issues
If ‘Who Dun It’ Dahlias are not blooming, insufficient sunlight (less than 6 hours daily) or excessive nitrogen fertilizer (promoting leafy growth over flowers) are common causes. Ensuring full sun exposure and using a balanced or low-nitrogen fertilizer can remedy this.
Yellowing leaves can indicate various issues. Overwatering or poor drainage can lead to root rot, causing leaves to yellow and wilt. Conversely, underwatering also causes yellowing, often with crispy edges. Nutrient deficiencies, particularly magnesium or iron, may cause yellow leaves with green veins; a soil test can confirm this, and fertilizers can address the imbalance. Pests like aphids or spider mites can also cause discoloration.
Wilting stems from either too much or too little water. Check soil moisture: if soggy, reduce watering; if dry, increase it. Wilting can also be a symptom of root rot due to poor drainage or fungal diseases, requiring addressing underlying soil conditions. Proper spacing and air circulation can prevent many of these common problems.