The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
Water is very important to impatiens. They appreciate moist soil, but it shouldn’t be soggy. If you have good soil with lots of organic material added each year and if your impatiens are well mulched, you will need to water them only when it has not rained for a week or two. If you have poor soil with little organic content and/or if you choose not to use mulch, then you may have to water impatiens almost every day that is sunny. This is particularly true for impatiens growing in containers.
You will know when impatiens need water. Their succulent stems and thin leaves wilt dramatically the minute they are deprived of sufficient moisture. They recover quickly, though, as soon as they are watered. Alternating extremes of wet and dry soil is stressful for impatiens, so try as much as possible to provide a fairly constant level of moisture throughout the growing season. Using a drip irrigation system attached to a timer is one way to achieve this goal. For information on products see the file on Choosing Watering Equipment
Impatiens do not require a rich diet. If you have soil with lots of organic content, the earthworms and microbes in that healthy soil provide the necessary nutrients in most cases. If you have poor soil or if you just want to be sure, a spoonful of general-purpose slow-acting granular fertilizer mixed into the soil or sprinkled on its surface at planting time is sufficient for the season for each plant. Be restrained. Overfeeding causes impatiens to produce lots of foliage and very few blossoms and they grow lank and leggy. The tender growth tends to attract aphids. Some gardeners give impatiens a boost in mid-summer with a spray of some kind of liquid fertilizer, but that step is optional.
Because they are fairly sensitive to soil moisture levels, impatiens do best when they are well mulched with some kind of organic material. A layer of mulch over the soil reduces soil moisture loss through evaporation, discourages weeds, and cools the soil. Best of all however, the organic mulch gradually decomposes and adds organic matter to the soil which is food for the microbes that keep the impatiens plants healthy. After planting seedlings, spread 2 or 3 inches of some organic material such as chopped leaves, wood chips, shredded bark or compost, if it is available, on the soil around the base of each impatiens plant. Canadian sphagnum peat moss is a good mulch only if it is mixed with something else. For more information see the file on Using Mulch
As they age over the season impatiens stems tend to become long and leggy, especially those in deep shade. Pinching the tips of these stems back 3 or 4 inches with your fingers or clipping them with pruners will temporarily stop the blooming, but plants will rebound with new branches, a more compact shape and renewed flowering.