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Primula spp.
Growing calendar
Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.
Guides
- Growing Primula from Seed: Chilling, Surface Sowing and Transplanting seedlings
- Primula Care: Damp Shade, Watering and Keeping Plants Year After Year
- Why Primulas Stop Flowering, and How to Get a Longer Spring Display
- Primula Growing Calendar: What to Do in Each Part of the Year
- Primula Problems: Vine Weevil, Slugs, Aphids and Brown Leaf Edges
Common problems
Start from what you can see on the plant.
Pests and diseases (15)
Problems recorded for this plant, most serious first.
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.
Rust
Disease
Small raised orange-yellow to red-brown pustules form on both leaf surfaces, then rupture and release powdery spores. Heavy infection yellows the leaves and kills them early.
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.
Bacterial Soft Rot
Disease
The crown or the head becomes water-soaked and soft, then collapses into a slimy mush. The rotting tissue gives off a distinctive foul odor.
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.
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.
Bacterial Speck
Disease
Small dark brown spots ringed by a yellow halo form on the leaves, and heavy infection burns off the whole leaf. Fruit carries scattered black pinpoint specks.
