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Dahlia pinnata
Growing calendar
Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.
Guides
- How to Plant Dahlia Tubers: Depth, Spacing and the Stake
- Dahlia Care Through Summer: Watering, Feeding and Staking
- Pinching and Disbudding Dahlias for More or Bigger Flowers
- The Dahlia Year: What to Do From Planting to Lifting
- Dahlia Pests: Slugs on Young Shoots and Earwigs in the Blooms
- Lifting and Storing Dahlia Tubers or Leaving Them in the Ground
Common problems
Start from what you can see on the plant.
Pests and diseases (24)
Problems recorded for this plant, most serious first.
Bacterial Wilt
Disease
Leaves wilt while still green during the day and recover in the morning and evening; after a few days of this the plant dies. Cut the stem and stand it in water and a milky white bacterial ooze streams out in threads.
Powdery Mildew
Disease
White patches appear scattered on the upper leaf surface at first, then the whole leaf is coated in a white powder. Leaves later yellow, brown and die back, and reduced photosynthesis cuts growth and yield.
Brown Leaf Spot
Disease
Small light brown to gray-brown spots form on the leaves and enlarge into irregular lesions. When they merge the whole leaf dies and plant vigor drops sharply.
Sclerotinia Rot
Disease
The crown, stem or head rots in a water-soaked way and is covered in white cottony mycelium. Black sclerotia later form inside and on the surface, and the plant wilts and dies.
Crown Gall
Disease
Irregular galls form at the crown and on the roots, gradually enlarging and turning woody. They block the flow of water and nutrients, so the plant loses vigor and may die.
Southern Blight
Disease
The stem rots at soil level and white silky mycelium spreads over the crown and the surrounding soil surface. Brown sclerotia the size of rapeseed then form and the plant wilts and dies rapidly.
Anthracnose
Disease
Light brown to dark brown round lesions with sharp margins form on leaves and fruit, slightly sunken in the center. In wet weather salmon-pink slimy spore masses ooze out on the lesions.
Damping-off
Disease
The stem pinches in at soil level, turning water-soaked to brown and thin, and the seedling topples over. Infection before emergence makes the stand uneven with missing plants.
Root Rot
Disease
Fine roots rot brown to blackish brown, growth stops and the lower leaves yellow. The plant wilts easily in the daytime and eventually dies outright.
Root-knot Nematode
Pest
The plant wilts in the daytime and does not recover with feeding or watering. Pull it up and the roots carry beaded chains of galls of varying size with few fine roots.
Gray Mold
Disease
Water-soaked brown lesions form on flowers, fruit and leaves, densely covered by a fuzzy gray mold. Fruit rots and drops, and decay continues in storage after harvest.
Verticillium Wilt
Disease
Only one side of the lower leaves yellows and wilts, and the symptom moves up the plant. Stem vascular tissue turns pale brown and the plant dies without ever growing well.
Leaf Spot
Disease
Small round brown to gray-white lesions appear on the lower leaves, the centers turning gray with tiny black specks. As they multiply the leaf yellows and drops early.
Ring Rot
Disease
The bark of branches and trunk becomes rough and warty, serving as the inoculum source. Fruit develops round brown lesions that soften and rot in concentric rings.
