Successful Impatien Planting

I've been growing and planting impatiens professionally for over 20 years in South Florida. I've pretty much learned what works and what doesn't work. Most of this will apply to all flowering annuals. Here are a few tips:

• Location: Impatiens are very versatile. They can do well in pretty heavy shade or direct sun. The ideal location would be where they get morning sun and afternoon shade. In other words, an eastern exposure. But they can work almost anywhere. In the more sun they will be more compact and have more flowers but will need more water. In heavy shade they will get a little leggy and you need to be careful that they don't stay too wet.
• Soil: For best results the Florida sand will be amended with some organic material such as peat moss. But drainage is very important, so don't make the soil too rich! If the area hasn't been planted in before and is just native sand, I usually add a good potting soil mixture that contains peat, pine bark and some perlite. In later years there is usually enough old soil and composting mulch that I don't add anything.
• Spacing: I usually plant small annuals on 12 inch centers (12" from the center of one plant to the center of the next plant) . This will usually result in very tall, very full plants within a month or two. If you don't want them too tall or don't want the look of a solid mass of plants then you can, of course plant them further apart. Any closer than that is usually just a waste of plants.
• Planting: Don't plant them too deep! Apparently in some parts of the country it is common to plant them deep. Not in Florida. It is best to plant them so that the soil level of the plant is about a quarter inch above the existing soil level. If you plant them too deep they will be much more likely to get fungus and rot off.
• Fertilizer: I have always gotten the best results with Osmocote. It is a slow release fertilizer that is widely available. One application will last about 3 months in South Florida conditions. I use about a half tablespoon per plant spread evenly across the bed after planting. Some people prefer to put the Osmocote in the hole as they plant each plant. There are arguments for each way and both seem to do o.k. but I prefer topdressing. That way as the fertilizer dissolves it washes down through the whole root zone. Some gardeners prefer to use a liquid feed like Miracle Grow. It can give you great results but has to be reapplied every couple of weeks. I also find that sometimes people tend to over fertilize with liquid feeding. This results in large, dark green plants but with few flowers. Its hard to go wrong with Osmocote.
• Mulch: I always mulch impatiens with a good shredded wood mulch like cypress or dyed mulch. It help maintain moisture in the soil, slows down weeds, looks great and enriches the soil as it deteriorates. About an inch to an inch and a half is plenty. Again, just make sure that the mulch is not up against the stem of the plant as it may cause it to rot off. I usually just cover all the visible soil between the plants but don't mulch under the branches.
• Watering: Water them in good after planting. The soil should be well saturated. Then watch them carefully for the first couple of weeks. It is best to water plants as needed rather than on a set schedule. The size of the plant, the location, the soil and the weather will all effect how often they need watering. In the winter time, low humidity and strong wind will dry out plants faster than bright sun and warmer weather. When the plants are first planted, they have small root systems. The roots can't reach as far or as deep for moisture, so they will need to be watered more often. As the plants become better established they will need water less often, probably a couple of times a week on average. Ideally the plants should be thoroughly watered and then left till they are just starting to wilt a little and then watered heavily again. If they wilt too much it will cause damage or death to the plant. If they are watered too much, they will get diseases and die. Pay attention to your plants and they will let you know when they need water.
• Maintenance: Impatiens in winter usually require very little maintenance. There are few insect pests in the cooler months. Sometimes caterpillars show up early in the season and sometimes spider mites arrive in the spring towards the end of the season. I use Sevin on the caterpillars. If mites get bad late in the season I usually just pull the plants at that point. If you plant in November, you may need to re fertilize in late February if the plants are looking a little yellow or thin.
  

With proper planting and a little attention, impatiens should last from November 1st until about May. That is over half a year. All in all few annuals will give you more bang for your buck.