How To Grow Impatiens
Some Impatiens are very easy to start and some are very difficult. Most of the annual types are fairly easy from seed, just needing a winter season to sprout and most of these are hardy as well. The perennial kinds can be a little more tricky. Many need to be sown right away in order for them to sprout or if this can not be done, keep them from drying out by wrapping them in a moist paper towel and sow them as soon as possible. Impatiens seeds of all kinds need light for germination so they have to be sown on the soilís surface. The soil should be well drained and moisture retentive; a good seed starting mixture is fine. I also find that a clear covering of plastic over the pots adds a little extra humidity and aids in germination. I then place the covered pots under lights a few inches from the florescent tubes or you can use whatever method works best for you. Some folks use heating mats set from 70 to 75 degrees Fahrenheit.
Perennial impatiens cuttings are very easy and definitely easier then seed. Impatiens annuals are always best by seed but cuttings can be done; it is just a little more difficult to get them to root. To do cuttings start with a strong stem with healthy leaves and remove the flowers and large flower buds. Cut the stem about 3 inches in length and just below a node. I have done cuttings less than a quarter of an inch in length and they rooted just fine, but I believe it is much easier on the cutting and you if the clipping is a little longer. Next pour moist perlite in a clear container (I have used one gallon water bottles with the top removed) and place the cutting in the medium. If you like you can use rooting hormone but for the most part I find I donít need it. Place some plastic wrap over the top and set a few inches under fluorescent lights at room temps. In about a weeks time they should start to show signs of roots. Oh! Donít forget to label your cuttings as well, this is very important if you are doing multiple types. Some people have found success just using a glass of water. I have found that the method I use gets better strikes than just plain water and if you are trying wild impatiens its best to use this way.
Next is the real fun part. Potting up your new babies. Everyone has their own potting soil mix that they like to use and it does change from region to region so this must always be in consideration. But, impatiens are hungry little plants and like to be well fed so try to get the richest loamy potting soil you can find. Here are some brands that I have tried or heard that have been very good. Personally I have tried Kellogís Patio Plus and can say I have very pleased with their mix. It has lots of stuff that impatiens love: bat guano, worm castings, seaweed, chicken manure and for drainage perlite. I tried this on a whim one day and my plants grew very quickly. Some folks may want to add some more perlite for thier region. Black Gold is another I have tried with good results. It is an organic mix much the same as Kellogís potting mix ingredients, but is more expensive, and needs perlite added for extra drainage. If you are one who likes to grow organically this one is the way to go. One that was recommended to me by a good friend is Miracle Grow. This is also a yummy mix and it has fertilizer and water polymers mixed in. The rule of thumb is basically a rich well-drained loamy blend. With these soils you donít need to fertilize right away. Liquids are good and I use time release pellets with good results. Donít over-fertilize this will cause the leaves to distort which looks a lot like pest damage with the critters. Over fertilization can also cause death to the plant I have learned this first hand. Just go by the recommended usage on the label. The best growing environment for impatiens are cool temperatures. Most species grow in rainy montane forests where temperatures rarely get very hot, mostly 60-78ļ F is the norm. If you live in an area with cool summers like the San Francisco Bay area you can grow most year around in the garden. But if you are like me and live in a hot summer area most need to be kept in a cool humid greenhouse.
The big pests for impatiens are mites, aphids, thrips and, white flies. It is always a good idea to keep an eye out for these pests and have a good program to keep them under control. Signs of infestation are distorted leaves or small yellow spots seen on top of the leaves. It is always best to strike them down quickly and donít let it get out of hand or they can spread and infect others. If you need to use sprays stay away from oil sprays. This may cause tip burn and make it harder for your plant to recover. I have heard of using soaps and alcohol mixtures working well. Using a standard spray bottle with a teaspoon of dish soap, not dish washing machine soap, and half filled with alcohol and topped off with water the rest of the way. Shake and spray the heck out of those little suckers. And remember tip pinching will help encourage branching and help them get bushier which leads to more flowering stems.