These rounded, flat-faced spring flowers look just like a chubby-faced baby, so how could you not love them? Garden favorites for generations, pansies are widely available just about everywhere and are often the first annuals to bloom. Unfortunately, since they're not heat resistent, you have to plan carefully to get the most out of them before the dog days of summer knock them flat on their adorable little faces. Here's what you need to know.
Pansies grow in most USDA Hardiness Zones and can even grow successfully in northern zones, like zone 4. They grow to be about 6 to 9 inches tall—making them good ground cover between taller plants growing on your plot—and bloom in a variety of bright colors like blue, lavender, purple, red, orange, bronze, yellow, and white. These annuals begin to bloom in early spring and continue through most of summer, and in milder climates, they can be seen blooming from autumn through the winter months. In hot climates, look for heat-resistant cultivars and plant them in moderate shade. They prefer full sun, but can grow successfully in moderate shade (they'll need more sunlight than the 51 Plants That Don't Need A Lot Of Sun To Thrive).
The easiest way to grow pansies from seed is to treat them like biennials. Sow them outdoors in midsummer, then plant them in their final home in the fall, mulching well in cold winter areas.
It's possible to sow pansies indoors in a container garden, although it is a bit of a challenge: Sow the seeds indoors 14 to 16 weeks before the last frost date, barely covering them. Place the containers in your refrigerator for 2 weeks and then expose the seed to room temperatures. Your plants should sprout in about 10 days.
After germination, keep the temperature as low as you can, between 50 and 65°F is ideal, but room temperature is acceptable. Plant out hardened-off seedlings as soon as the soil is workable. When they are outdoors, water pansies as needed and deadhead them to help maintain blooming. Cut straggly plants back severely to stimulate new growth.
As one of the few annuals that can be planted in fall for early-spring bloom, pansies play a unique role in the garden and are wonderful if you're considering a companion planting method for your garden. Tuck them around plants that thrive in part shade, such as ferns or purple-leaved heucheras, and they'll bloom well into summer.
Pansies are somewhat susceptible to leaf diseases, so choose disease-resistant strains, and rotate plantings if you notice repeated damage. Hand-pick slugs and snails if they become a problem.