How to Grow and Care for Impatiens

Impatiens (Impatiens walleriani) plants are one of the most popular bedding plants due to their brightly-colored, profuse blooms and their ability to grow in shady areas. Although they are technically perennial plants in tropical zones, impatiens are more often grown as annuals, where their spring-to-fall blooming season fills the garden with color. Standard impatiens blooms come in a variety of colors, including white, red, pink, violet, coral, purple, and a recently-introduced color: yellow.

In northern United States and areas with similarly cold winters, the traditional time for planting impatiens is in the spring is when the danger of frost has passed.

Impatiens Care

Impatiens flowers have long been one of the dominant bedding plants in North America, especially for shady areas. They are also used in container gardens, ranging from hanging baskets to window boxes. Most often, impatiens are planted from nursery seedlings that are already near flowering maturity though they can be grown from seeds and cuttings.

How to Plant Impatiens

Plant impatiens in any moist, well-drained soil in a shady or semi-shady location. It's best to plant them in late spring after the soil has warmed to at least 60 degrees Fahrenheit. If planted in soil that is too cold, the plants will languish for the entire growing season. Space the plants 10 to 12 inches apart. After planting, pinching back the stems will encourage bushy growth.

In a container of plants that prefer shade, impatiens will grow wonderfully if both the container and potting medium have good drainage—any pot material will do. As a general rule, plant one plant for every three to four inches of pot diameter. Use a standard commercial potting mix. Container-grown plants require more fertilizer and water than garden-grown plants.

New Guinea impatiens also work especially well as a filler plant in containers but they require much more direct sunlight than the standard impatiens.

Light

With sufficient water, standard impatiens can be grown in a partial sun location in northerly regions, but their greatest virtue is that they thrive in the shade. In fact, they're among the relatively few readily available, inexpensive flowering plants that will put on a great summer-long floral display even when grown in full shade.

Soil

Grow impatiens in well-drained soil enriched with organic material. They prefer a slightly acidic soil with a pH range of 6.0–6.5. The soil must drain well to avoid becoming soggy from the frequent watering that impatiens require.

Water

Once in the ground, standard impatiens need at least two inches of water per week. When temperatures average consistently above 80 degrees Fahrenheit, you might have to double that amount. In window boxes and hanging pots, impatiens might require daily watering, especially if the daytime temperature rises above 85 degrees Fahrenheit.

Temperature and Humidity

Impatiens are quite sensitive to heat. If there has been a long dry spell, your plants will likely look wilted. Thankfully, they bounce back quickly once they are hydrated. Impatiens are fine growing in humid weather.

Fertilizer

Impatiens will flower best if regularly fertilized with a water-soluble fertilizer every two weeks throughout the spring and summer. Another option is a slow-release granular fertilizer used at the beginning of the spring and again halfway through the summer. For the amount to use, follow product label instructions.

Recommended Varieties of Impatiens

More than a thousand varieties of impatiens are available. Impatiens that are resistant to downy mildew disease might be hard to find because downy mildew-resistant varieties are still being developed and introduced to the market. To avoid the disease, your best choice might be to plant New Guinea impatiens because they are by nature resistant to downy mildew.

Some recommended varieties of standard and New Guinea impatiens include:

• Impatiens walleriana 'Imara XDR': Is a new disease-resistant line of standard impatiens from the Syngenta company, which became available in 2019. There are seven colors as well as color mixes in this series, which promises to restore standard impatiens to their former popularity.
• Impatiens walleriana 'Beacon®': This is another series of standard impatiens that is "highly resistant" to mildew, introduced in 2020. Beacon is derived from the Super Elfin line, with many colors available.
• Impatiens hawkeri 'Celebration' series: This is one of the best of the New Guinea impatiens. Available in a wide range of vibrant colors, these plants grow up to 16 inches tall. These plants were likely hybridized with other species of impatiens.
• Impatiens x 'Bounce™' series: Developed by Ball Horticultural Company, this hybrid series of impatiens is a cross between New Guinea and standard impatiens. According to the company, they are resistant to downy mildew and thrive in sun and shade. It bounces back nicely after wilting in hot weather.
• Impatiens x 'SunPatiens®' series: This variety thrives in full sun and has unusually large flowers (up to three inches across) that are available in unique shades (such as salmon and lilac). Growing up to three to four feet tall, the Sunpatiens series is across between New Guinea impatiens and standard impatiens species.

Pruning

If your impatiens plants become leggy late in the heat of summer, use sterile, sharp garden scissors to trim off the top third of their vegetation. This will promote the emergence of new blooms and improve the overall appearance of the plants.

Propagating Impatiens

Impatiens will readily self-seed themselves, even in colder climates, though it might take most of the following year's growing season before the seeds produce flowering plants. For this reason, it is easier to propagate impatiens from cuttings taken in the fall. Here's how to propagate impatiens with cuttings:

1. Using a sterile, sharp cutting tool, clip a plant shoot four to six inches long, with ample leaves. Pinch off the bottom sets of leaves as well as any flowers or seed pods.
2. Suspend the cutting in water and place it in a bright area but out of direct sunlight. Replace the water frequently (every few days) as it becomes cloudy.
3. When a good network of roots has developed, plant the cutting in potting soil or a mixture of soil and vermiculite or perlite. Continue to grow them in a bright area out of direct sunlight. Keep the potting soil consistently moist.
4. Harden off the plants to gradually introduce them to sunlight before planting them outdoors.
5. Plant into the garden or in outdoor containers after the last frost date in spring.

How to Grow Impatiens From Seed

Impatiens take their name from the Latin, impatiens, meaning impatient. They are so-called because their ripe seed pods will sometimes burst open from even a light touch (as if they were impatient to open).

Some gardeners also collect seeds from the pods that the plants produce in late summer and fall and then start the seeds indoors in a seed-starting mix in later winter, six to ten weeks before the last frost. When impatiens are planted from seed, it can take several months for them to mature into flowering plants.

Here's how to plant impatiens from seed:

1. Fill small pots or cell packs with moistened seed-starter mix or potting soil.
2. Place one or two seeds in each pot or cell about 1/2 inch deep and cover with mix.
3. To maintain moisture, cover the pots or cell packs with a piece of plastic or glass to create a mini greenhouse.
4. Place the seeds in a warm location out of direct sunlight. The growing medium temperature should be between 70 to 75 degrees Fahrenheit.
5. Remove the plastic or glass covering once germination takes place, which should occur in 14 to 21 days.
6. Place the young seedlings in a sunny, south-facing window or under fluorescent lights. Position lights about four inches above the seedlings for 12 to 16 hours each day.
7. Fertilize every other week with a quarter strength water-soluble fertilizer.
8. When the seedlings are a few inches tall, harden them off to gradually expose them to sunlight before planting them outdoors. Do not plant them outdoors until after the danger of frost has passed.

Potting and Repotting Impatiens

It's generally not necessary to repot impatiens, as they are usually discarded at the end of the growing season. Although these plants are perennial in warm climates, they can be susceptible to mites and other insect pests when moved indoors. The best strategy is to cut back the stems to three inches or so, then give them a sunny location and slightly less water through the winter. Withhold fertilizer through the winter months. Although these plants do not go dormant, they are most likely to survive if allowed to slow down their growth for the winter months.

Overwintering

Impatiens are tropical plants that will succumb to the first light frost. Pull up and discard these plants to prevent pathogens from overwintering. Potted plants can be similarly discarded or bring them indoors if you plan to keep them over the colder months.

Common Pests & Plant Diseases

The popular impatiens fell out of favor in 2004, when a particular form of downy mildew appeared and quickly decimated breeding stock in commercial nurseries across North America. This disease is caused by a pathogen called Plasmopara obducens, and for more than a decade, it virtually stopped all commercial sale of standard impatiens. Standard impatiens did not begin a comeback until 2019, with the development of a few mildew-resistant hybrids.

Aside from the downy mildew that devastated the standard impatiens, these plants can be affected by viruses, fungal blights, and rots. These problems are more likely in humid, wet conditions, or where plants are crowded closely together.

Impatiens can experience problems with insects, including aphids, mealybugs, thrips, whiteflies, slugs, snails, and spider mites. Severely affected plants can be removed; minor infestations can be treated with horticultural oils.

How to Get Impatiens to Bloom

Impatiens are among the most prolific bloomers of all flowering plants. You can generally expect abundant blossoms from late spring until the first killing frost in the fall. If your impatiens are blooming less robustly than you would like, try pruning back the leggy stems to stimulate branching and new bud growth. Reduced blooming can also be the result of too much sun, not enough water, or too much fertilizer.

Common Problems With Impatiens

Though these easy-to-grow blooms can generally be left alone, they will present a couple of common challenges.

Legginess

One possible cause of impatiens becoming leggy is over-fertilization.

Scorched Leaves

Too much sun can scorch the leaves on most varieties of impatiens, though the New Guinea varieties can usually tolerate full sun if given extra moisture.