How to Choose and Grow the Prettiest Pansies for Cool-Season Color
These flowers brighten up containers and garden beds during the cooler months in spring and fall. Plus you can overwinter them to get more than one season of bloom.
If you live in a warmer region of the country, you might already know that pansies can be planted in the fall and they'll continue to grow and bloom all winter and into spring. But pansies are hardy in parts of the northern U.S. and southern Canada, so you can overwinter them as far north as Zone 4. That means if you plant them in the autumn, pansies can last up to eight months, from September to April or May, providing colorful blooms for much of that time. They usually aren't very pretty in the dead of winter, but their spring blooms can be even more robust when the plants have been in the ground since fall.
Pansies vs. Violas
Pansies (Viola x wittrockiana) are viola hybrids with a complex ancestry that includes several different species. They're short-lived perennials but are mostly grown as annuals or biennials. Similar to pansies and offered in garden centers at the same time are closely related Johnny jump-ups (Viola tricolor) and Viola 'Jackanapes'. Both of these have hardiness similar to pansies.
Pansies come in series that offer the same plant and flower characteristics but in a variety of bloom colors. This gives you great flexibility in working with flower color because you can buy individual colors from a series, or a mix of colors from the same series.
If you want your fall-planted pansies to rebloom in the spring, you'll need to give them a little extra TLC over the winter.
Plant as Early as Possible
The more established the plants are, the better they'll be able to withstand cold winter conditions. That means planting in September, if possible. The farther south you are, the wider your planting window, and October may also be acceptable in warmer Zones. But in Zones 4-7, early planting is key.
Choose Healthy Plants and Hardy Varieties
Healthy plants establish more quickly, rapidly growing the root system that's so critical to winter hardiness. Then, you also need to choose a hardy variety. Generally, varieties with medium-size flowers overwinter better than large-flowered types, but there are several exceptions. In any case, obtaining the very hardiest cultivars is only a concern in northern areas such as Zones 4 and 5. Varieties that overwinter well include the Sky, Delta, and Accord Series. Icicle pansies (and violas) have been bred specifically for cold hardiness and also have done well in Zone 4. Other pansies that are reported to grow well in the north are Crystal Bowl, Universal, and Maxim.
Plant in an Area with Good Drainage
Pansies are susceptible to root rot in overly saturated soil. They have been known to overwinter successfully, only to succumb to excessive moisture as the winter's snow and ice begin to melt. Be sure they're growing in a well-drained location.
Mixing Pansies with Bulbs
A technique gaining in popularity is to plant spring-blooming bulbs in fall in the usual fashion, then install pansies in the same bed, right over the bulbs. The bulbs will emerge and bloom as usual in spring. When their flowers die down, the pansies will just be starting their spring bloom, providing additional color while the bulb foliage ripens. This is a great way to get more color from your beds until it's time to plant summer annuals.
Shopping for Pansies
Pansies don't have a long shelf life in cell packs. They stretch out quickly, and once they do, they'll never do as well when planted. Garden centers often sell older, stretched out plants at a discount, but resist the temptation to buy them.
Healthy pansies are compact, have minimal leaf yellowing, and probably show fewer blooms while in the packs because they're younger plants. Despite the lack of color at the time of purchase, these are the plants you want. When you find cell packs that look good, pop a few plants out and look at the roots. They should be white, not brown, and should be well developed throughout the whole soil plug.
You'll find a better selection of healthy plants earlier in the fall season, so don't delay. September is the month that pansies begin to appear in nurseries in most regions. Many gardeners swear by field-grown pansies, which are sown outdoors and lifted into flats when ready for sale. For either field-grown or cell pack pansies, the same rules apply: Look for compact, healthy plants.
How to Grow Pansies
Pansies are not difficult to grow. Good soil, steady moisture, and at least partial sun will provide the results you're looking for. What they don't tolerate is heat and humidity, which is why they thrive in spring and fall.
Plant pansies 6 to 8 inches apart. They can be used as borders, or in larger masses, but don't count on a solid ground cover. The plants are more clumping than spreading. Pansies respond well to regular deadheading. As often as possible, every couple of days if you can, pinch off faded blooms and any fruit (small green seed capsules) that may be forming. This will spur plants to continue blooming.
If you apply a mild fertilizer at fall planting and every four to five weeks in spring, your pansies will have plenty of nutrients to fuel all their growth and flowering. Pests are not a major issue with pansies, but slugs and snails love them, so control may be necessary from time to time. Aphids can also crop up occasionally. Leaf diseases, particularly mildews, are fairly common, and the occasional plant will die from root or crown rot, so take care not to bury the stems or crowns when planting. Healthy plants and good growing conditions (ample sun, fertile soil, and good drainage) will keep pest problems to a minimum.
Heat causes pansies to become leggy and stop blooming. So when summer warmth begins to get the upper hand, go ahead and remove pansies to make way for your summer annuals.