Winter Survival of Pansies

Fall Planting

• Young pansies set out in fall have time to establish before winter cold sets in. Once soil temperatures drop to between 45 and 65 degrees Fahrenheit the pansies begin putting on their best root growth. Once the temperature drops below 45 degrees Fahrenheit the pansies enter a dormant state. Planting four to six weeks before the first expected frost ensures the soil is cool enough for healthy growth, but also gives the plants time to establish before the ground begins to freeze.

Site Needs

• Sites that receive at least six hours of direct winter sunlight provide the best location for winter pansies. Shaded beds suitable for summer pansies receive too little sun in the short days of winter. Planting sites must drain well, otherwise the collected water in the soil may freeze and kill the pansy roots. Beds with rich well-drained soils provide the best site for a winter bed. Working compost into the soil before you plant helps improve the drainage in the site.

Mulching

• Mulch insulates the pansy roots from the cold and also from damage from frequent winter temperature fluctuations. Pine straw and bark mulches laid at a 2-inch depth immediately after planting provides instant insulation for the roots without covering the plants and preventing them from receiving sunlight. A mulched bed also dries out less slowly in the cold winds often present during the winter months.

Winter Care

• Temperatures below 25 degrees Fahrenheit kills pansy foliage. Minor foliage dieback doesn't permanently affect the plants. Increasing the mulch layer to a 4-inch depth once the temperatures drop covers the plants and protects them from the cold, but the excess mulch must be removed from the plants once temperatures warm. The pansies survive as long as the soil doesn't freeze completely around the root ball. Watering the plants as necessary to keep the soil moist but not soggy ensures the plants don't become dehydrated during the winter months.