CARE OF GREENHOUSE AZALEAS
Photo: Neil Anderson
When you are shopping for an azalea plant, choose one with a few flowers open and color showing in most of the buds so that you, or the person receiving the plant, can enjoy watching it open and will get the most blooming time out of it. Plants with most of their flowers wide open may be showier to begin with, but will not last as long.
Getting the Most Out of Your Blooming Plant
A greenhouse azalea needs plenty of water. Check it daily to make sure it is continuously moist. When the top layer of soil in the pot feels dry to the touch , water the plant thoroughly (best done in a sink over a rack) and allow it to drain freely through the drainage holes in the bottom of the pot. If the plant was watered over a saucer, be sure to drain it after 15 minutes. A great way to double check whether you should water the azalea is to lift the plant periodically, comparing its weight to how heavy it seemed after you last watered it. Eventually you will know when it's ready to be watered, just by lifting the pot.
If the plant gets too dry, wait about 15 minutes after the first watering and repeat watering in the same way. If the plant still feels light when you lift it you may need to plunge the whole potted plant into a pail of water and allow it to soak until no more bubbles appear. Unfortunately when an azalea is allowed to get this dry it almost always drops a lot of leaves soon after and may even die.
While the azalea is blooming, keep it close to a window where it can receive at least 4 hours of indirect sunlight per day. Try to keep temperatures as close to ideal as you can. Night temperatures between 45° and 55° F and day temperatures that do not exceed 68° are the goal. Since this plant requires low night temperatures, it will probably have to be set in a cool entranceway or enclosed porch during the evening. The plant will probably tolerate a less than ideal location for a few days as long as you return it to a better place shortly thereafter. There is no need to fertilize while the plant is blooming.
After Blooming - Azalea Care
If you decide you want to force your azalea to bloom the following year, prune off the faded blossoms and shape the plant so that it maintains a bushy, well-branched habit. If the plant is healthy with no disease symptoms (root rotting , leaf dropping) occurring, re-pot it into a container that is only one size larger than the old pot (about an inch or so larger in diameter.) Use a potting medium that is 2 parts peat moss, 1 part packaged potting soil, and 1 part sand or perlite, or use any fresh potting soil rich in peat moss.
Keep the plant in a bright, sunny location and water as described earlier. Start fertilizing with an acid-forming fertilizer every two weeks until new flower buds develop next fall or winter. If the leaves turn yellow between the veins, apply a chelated iron product according to package directions.
After all danger of frost has passed in spring, put the plant outdoors. Sink the pot into the soil up to its rim, in a well drained, partially shaded site. The azalea will dry out faster in a pot plunged into the earth than if it were planted directly into the ground because the roots can not spread out in search of moisture. Therefore special care must be taken with regard to watering, especially during hot, dry periods.
The following requirements may be difficult to provide and are why many people simply discard azaleas once they've finished blooming:
In order to form flower buds and ultimately bloom again, your azalea will need 5-6 weeks of night temperatures between 40° and 55° F. Some or all of this temperature requirement can be met outdoors in the fall depending on the year. However, when frost threatens, the plant must be moved indoors and grown under a cool night regimen. That's the tricky part. Warmer temperatures will cause a skimpy supply of flowers. Without a high enough level of humidity around the plant at this stage, the buds may be deformed. Tiny green shoots may develop. These should be removed for aesthetic purposes.
Once flower buds are well developed, after 5 or 6 weeks of "cold treatment", move the plant to a sunny window and repeat the same instructions given in the paragraphs under "Getting the Most Out of Your Blooming Plant". The azalea should bloom again for several weeks in its new location.