Background

Pansies are flowering, cool-season biennials often treated as annuals. Most types grow in a mounding habit to 8 or 9 inches in height, with a spread of 1.5 to 3 feet across. The foliage is a rich, attractive green, while the flowers are whimsical, five-petaled beauties that come in a range of vibrant shades, including whites, pinks, purples, blues, reds, oranges and yellows, as well as bi-color combinations.

Blooms can be expected in spring, summer and sometimes fall (after a late-summer rest) in cold-winter regions, and in winter and spring in milder climates. Generally speaking, gardeners in cooler northern climates will enjoy flowers longer than their counterparts in the South, where higher soil and air temperatures tend to abbreviate the blossoming season.

How to Care for Pansies

Planting.  Pansies may be planted as bedding plants or from seeds (see Propagation). Buy bedding plants that are just beginning to bud, and show healthy green leaves with no spotting or wilting. Roots should be developed enough to hold soil together, but not rootbound. Planting time is in early spring for spring/summer blooms in cold-winter climates, in fall for winter/spring blooms in milder climates.

• Select a site with loose, well-drained soil either in full sun or partial shade.
• If establishing a new flower bed, clear the planting site of weeds using a non-selective herbicide in accordance with package instructions. Wait 48 hours, then cultivate the bed to a depth of six to eight inches, amending the soil with rich, organic materials such as compost, or pre-packaged garden soils and planting mixes.
• Dig a separate hole for each plant in your bed, then set plants in holes so they are level with the surface of the soil. 
• When backfilling a planting hole, do so carefully and evenly to eliminate air pockets. If using a slow-release plant food, mix it into the backfill soil at time of planting.
• Water thoroughly immediately after planting.
• Add a two to three-inch layer of light, organic mulch around your new plantings to defend against weeds, help retain moisture and keep the ground cool.

Light, Temperature and Humidity.  Pansies can be grown in either full sun or partial shade; they tolerate heat better than most other violas; and they are highly resistant to cold, which means you can establish them outdoors as much as a month prior to the frost-free date in your area, provided the plants have hardened off.

Feeding.  If using a slow-release plant food, mix it into the backfill soil at time of planting. Otherwise, sprinkle a granular fertilizer around the plants after planting, or feed weekly with water soluble plant food. To feed large areas, use a hose-end feeder.

Watering. Pansies have average water needs, requiring three-quarters to one inch of moisture per week through rainfall or watering. Keep the soil moist at all times, but never saturated or soggy. Lastly, be sure to check your plants regularly during hot and/or dry spells as pansies (like violets in general) do not tolerate drought well.

Insect and Disease Control. Pansies are relatively problem free, but can suffer from some diseases and pests common to many ornamental plants. Most diseases involving leafspot and crown or root rot can be avoided by careful watering and mulching around plants to prevent soil-borne fungal spores from splashing up onto leaves. Many fungal leaf diseases can also be prevented and controlled by using a fungicide early in the season before diseases present themselves.

Insects may include aphids and spider mites. These can be treated with pyrethrin insect sprays. Slugs and snails may also damage pansies, and can be controlled with an iron phosphate slug and snail bait.

Propagation. Pansies may be propagated from cuttings, but are usually started from seed. Gardeners in cold-winter climates should start seeds indoors in winter for spring planting, while gardeners who live in mild-winter climates should sow indoors in mid to late-summer for outdoor planting in fall.

• Sow seeds in a flat, using a seed starter planting mix, then chill in the refrigerator for four to five days.
• After chilling, move the flat to a cool, dark place with a temperature between 65 and 70 degrees Fahrenheit. Sprouts should begin to appear within ten to twenty days.
• Once the seedlings have sprouted, grow them in a cool (50-60 degrees F) environment until they are large enough to be transplanted outdoors.
• After your young plants have hardened off, transplant them in the garden as you would if working from bedding plants. 

Deadheading: Promptly remove spent flowers while your pansies are in bloom in order to prevent them from setting seed. This will not only stimulate increased bloom production, but also help lengthen the plant's bloom cycle.