Viola Growing Guide: Planting, Care & Harvest

Viola cornuta

Growing calendar

Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.

JanFebMarAprMayJunJulAugSepOctNovDec

Sow / plantGrowingFlowering

Guides

Common problems

Start from what you can see on the plant.

Wilting Yellow leaves Leaves dying White powder Leaf spots Fruit problems

Pests and diseases (22)

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.

Late Blight

Disease

Dark green water-soaked lesions appear on the leaves and expand quickly into brown dead tissue. White mold forms on the underside and at the lesion edge, and dark brown lesions spread to stems and fruit.

Citrus Melanose

Disease

Tiny dark brown specks are scattered over fruit and leaves, sometimes clustering into tear-streaks or a sandpaper texture. Heavy infection makes the rind rough and badly cuts appearance value.

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.

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.

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 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.

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.

Downy Mildew

Disease

Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.

ScabMosaic DiseasePlant-parasitic NematodesFusarium Wilt and Damping-offLeaf BlightFoliar NematodeLeaf RotBlack MoldAlternaria Black SpotSmut

Written byYasuGrowing vegetables and fruit in Chiba, Japan, and building Gadenin. Corrections are welcome. 15 years of growing.