Posted by Brent Wilson on 9/1/2016 to Fertilizing & Watering Tips
Azaleas, Camellias and Rhododendron are easy to grow when planted in the right USDA Zone, the right exposure to sunlight, the right soil, and proper fertilization. Though some varieties will tolerate full sun, for peak performance, most prefer afternoon shade, particularly in the hotter regions of the South. Moist, but well-drained soil is a must. Azaleas, camellias and rhododendrons will not tolerate wet feet. Humus-rich, fertile soil is preferred.
Fertilizing at Planting Time
When planting azaleas, camellias and rhododendrons in less that fertile soil that is low in organic matter, it's good to mix an organic soil amendment, such as mushroom compost, composted manure, or your own homemade compost, at a 50/50 ratio with the soil removed from the planting hole. This will help to get your plants off to a good start by stimulating root growth. Newly planted azaleas, camellia and rhododendrons can also be watered with a solution of Root Stimulator.
When to Fertilize
During the first spring, fertilize your azaleas, camellias, and rhododendrons just as the flower buds start to pop some color. Fertilize again, if needed, lightly in late summer, but no later than 60 days prior to the average first frost date in your area. Late feeding could encourage new growth that might be damaged by a freeze, which can compromise the overall health of your plants.
Note: Because Encore Azaleas produce new flower buds every time new growth is produced, feed them right when each bloom cycle begins to encourage new growth and more flowers!
What To Fertilizer With?
Azaleas, camellias and rhododendrons prefer an acid soil so fertilize them with an Azalea, Camellia & Rhododendron fertilizer or a shrub and tree fertilizer that contain sulfur and/or iron. Avoid using fertilizers that contain much more than 10% nitrogen (the first number in fertilizer) and more than 20% phosphorous (the middle number). Refer to product label for application rates and instructions.
Alternatively, you can feed you azaleas, camellias and rhododendrons with a natural or organic plant food. Some folks don't ever feed these plants with man-made fertilizers. They simply mulch plants in early spring with organic compost or rotted leaves.
Note: If the leaves on your azalea, camellia or rhododendron turn pale green or yellowish this could be an indicator of iron deficiency, or soil that is too alkaline.
Azaleas, camellias and rhododendrons grow best in an acid soil ranging from 4.5 to 6.5 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0.
Testing Soil pH
Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline.
If you're unsure about the pH of your soil, and whether or not it's suitable for growing azaleas, camellias and rhododendrons, it's a good idea to test the pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.
NOTE: Yellowing or fading of leaves can also be an indicator of insect infestation from chlorophyll-sucking insects or from soil that is constantly wet or soggy. When foliage is discolored, first check the undersides of leaves for the presence of lace bugs, aphids or other insects. If you find damaging insects use an insecticide such as Malathion or Neem Oil to control them. Azaleas, camellias and rhododendrons do not like wet feet, which can cause yellow or browning of foliage. If the soil stays constantly wet, you might need to reduce watering or, to ensure good drainage, you might need to lift the plants and replant them in a mound or to another area in the landscape.
Azaleas, camellias and rhododendrons prefer a moist but well-drained soil when establishing themselves, however are quite drought tolerant when established. These plants do not like constantly soggy or wet soil conditions, which often leads to the onset of root rot and other harmful plant diseases. So be careful not to over water!
Before reading the watering tips further below, it is important to make sure that the soil in a planting area is draining properly. If you have recently planted a shrub, tree or other plant in the ground and the leaves are spotting, browning or blackening on the tips or elsewhere on the leaf, this could be a sign of oversaturated soil, which can starve the roots of oxygen and lead to root rot and other harmful plant diseases.
If you suspect there may be a soil drainage problem, whether poorly drained and constantly soggy or quick-draining and too dry, it's a good idea to test soil drainage.
How To Test Soil Drainage
To test soil drainage, dig a hole 12" wide by 12" deep in the planting area. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and the need for more frequent watering in the absence of rainfall or the addition of peat moss or other organic matter to the soil to help retain more moisture in the soil. A slower rate indicates poor draining soil and is a caution you need to improve soil drainage in the site, replant the plant(s) in a raised mound, or look for plants that are more tolerant of wet or boggy conditions.
How To Water
At Planting Time
Immediately after planting deep soak the soil in the planting area, including the root ball, to a depth equal to the height of the root ball. For an extra boost, to stimulate early root formation and stronger root development you can also water you new plants with a solution of Root Stimulator, which reduces transplant shock and promotes greener, more vigorous plants. When planted during the winter dormant season plants will require less water. So, be extra careful not to overwater during winter!
During the First Active Growth Season
In average garden soil you should not have to water your newly planted plants every day. More often than not, this causes soggy soil conditions that can lead to root rot and other plant diseases. In the absence of sufficient rainfall, water only as needed to keep the rootball and surrounding soil damp to moist. Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day. Plants planted during the winter dormant season, when plants are not actively growing and evaporation is much slower, will require much less water. So, be extra careful not to overwater during winter!
When established, azaleas, camellias and rhododendrons are moderately drought tolerant plants. Only during periods of dry weather will they require supplemental irrigation. Wilting leaves during a drought is an indicator that your plants could use a good deep soaking. Always check soil moisture before watering.
Tip: When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night, which can lead to the onset of fungus and other foliar diseases. Check soil moisture within a few days after planting and adjust your irrigation system accordingly to provide only enough water to keep soil moist, but not soggy.
Plant Long & Prosper!™
Questions? Contact Us!