How to Plant Azaleas
Plant azaleas in partially shaded spots and acidic, organically rich soil. Spread an organic mulch after planting.
Azaleas (Rhododendron spp.) are versatile shrubs that feature trumpet-shaped blooms in shades of orange, red, pink, white and purple. Hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9, the group includes varieties that range from 8 inches to 20 feet tall, meeting most landscaping needs, such as ground cover, shrub borders or large, specimen plants.
Partially shaded spots and freely draining, acidic soil high in organic matter provide the best results with azaleas. The shrubs should be mulched to retain soil moisture and avoid disturbance to the shallow roots.
Planting Time
Fall is the best time for planting azaleas. Providing the ground isn't frozen and the plants are well watered afterward, azaleas can be planted at any time of year, but fall planting usually gives the best results. In cold zones, the shrubs can develop their root systems before winter, and in hot climates, azaleas can become established before hot summer weather the following year.
In areas that experience frosts, plant azaleas six weeks before the first average local frost date. In warm zones, plant azaleas when the plants have stopped producing new shoots.
Acidic Soil
Soil between pH 4.5 and 6.0 is best for growing azaleas. A home soil test kit can tell you the pH of your soil. Azaleas that grow in a soil with a pH higher than 6.0 develop deficiencies of nutrients such as iron, which causes yellow veins on leaves.
You can lower soil pH temporarily with soil amendments, but the soil returns to its original pH over time. Applying sulfur at a rate of 1 1/2 ounce per 10 square feet lowers soil pH. Sprinkle the sulfur evenly over the soil surface and mix it into the soil to a depth of 10 inches.
Warning
Excess sulfur damages plant roots. Don't apply more than 1 pound of sulfur per 100 square feet, and don't apply sulfur more than three times per year.
Tip
Before planting a bed of azaleas, improve the soil by spreading a 4- or 5-inch layer of pine bark, compost or peat and mixing it into the soil with a garden fork to a depth of 10 inches.
Into the Ground
Step 1
Dig a hole twice as wide and the same depth as the azalea root ball.
Step 2
Remove the azalea from its container or remove any covering and ties.
Step 3
Place the azalea in the hole at its original growing depth, and scoop dug soil into the hole to fill in the gaps.
Step 4
Firm the soil with your hands.
Step 5
Water the azalea to moisten the soil to a depth of 10 to 12 inches.
Tip
Space azaleas according to their final growing widths. For example, space azaleas that grow 2 feet wide so that the main stem of one plant is 2 feet from the main stem of the next. If you don't know the final growing width of a variety, space the shrubs 3 to 5 feet apart.
Step 6
Spread a layer of leaf mold, compost, shredded bark or another organic mulch 2 to 3 inches deep around the azaleas. Don't pile the mulch against the azalea stems.
Water Needs
Azaleas thrive in moist soil and grow poorly when soil dries out. Water newly planted shrubs growing in average or moist soil whenever the soil surface is dry.
Newly planted azaleas growing in dry soils may need water two or three times a week while the shrubs are growing. Established azaleas need 3/4 to 1 inch of water every 10 to 14 days during dry weather.
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