Florist azalea (Rhododendron simsii) is regularly offered as a gift plant, especially during the winter season. However, it is also an excellent houseplant that can bloom profusely from year to year, with each bloom lasting weeks, if not months. Make no bones about it: this is a demanding plant, not something I would recommend to a beginner houseplant, but it is possible to keep it alive and well for many years if you are very careful.
This subtropical plant needs a bright and cool location with some direct sun in the winter and also fairly good humidity. However, in the summer you should seriously consider moving this plant to a shady spot outdoors. There are several reasons for this move, but one of the most important is that the Flower Azalea does not tolerate tap water very well. Whether it comes from a well or a municipal system, tap water tends to be hard (rich in calcium) and azaleas do not tolerate calcium. They like acidic soil and soft water. Therefore, after a winter indoors, they will greatly appreciate rainwater, as it is calcium-free and usually even quite acidic. Repeated rains during the summer will help rid the plant’s soil of excess calcium, making your plant very happy. In areas where summer rains are infrequent, it’s probably best to either save winter rainwater for summer or water your azalea with distilled water year-round.
Fertilizing this plant is also difficult, for the same reason: most fertilizers are high in calcium. While there are fertilizers for acid-loving plants (often labeled “azalea and rhododendron fertilizer”), conventional all-purpose fertilizers can be used as long as you dilute them to 1/4 the recommended amount…. and let Mother Nature leach the excess calcium from the soil during the summer.
Leave your azalea outdoors well into the fall, as flowering is initiated by several weeks of cool temperatures (between 4 and 13 ° C). In my area, where frost comes very early, I leave my azaleas outside until late fall, but bring them indoors on frosty nights and put them back outside the next morning when it warms up. As the cool treatment progresses, you’ll see plump flower buds forming at the ends of the branches – a sure sign that you’re doing everything right.
As a rule, you will find that your home-grown flower azalea is not completely covered with flowers, as is the case with commercial azaleas “straight from the greenhouse”, but that it forms clusters of flowers shortly after being put away, which last until spring, providing a much longer show than the first year. Personally, I prefer 4 months of moderate bloom to 3 weeks of intense bloom. Don’t you?
Finally, one last tip: Whether indoors or outdoors, in warm or cool weather, make sure your azalea never gets too little water. With its extremely fine roots that soak up every drop you water, and its abundance of tiny leaves and flowers that transpire massively, its potting mix can dry out very quickly. Therefore, especially during the flowering period, you need to check on your azalea at least twice a week and water as soon as the soil feels dry.