How do you treat rhododendron disease?
The fungus survives in the soil and cannot be eradicated once an area is infected. Chemicals that are available will only suppress disease and not cure an infected plant. Fungicides available for use on azaleas and rhododendrons include metalaxyl and mefenoxam. Apply all chemicals according to directions on the label.
What to spray on rhododendrons for bugs?
Apply horticultural oil sprays at a 2% solution (5 tablespoons oil per gallon of water). Insecticidal soap sprays during the growing season will help control crawlers and adults of soft scales, like the azalea bark scale.
What bug is eating my rhododendron?
Root weevils
Root weevils: Root weevils are universally the most serious pests of rhododendrons. Several species of root weevils feed on this plant group. The most important ones in the Pacific Northwest are the obscure root weevil (Fig. 1) and the black vine weevil.
What is eating holes in my rhododendron leaves?
Rhododendron varieties that are susceptible to damage should be grown in more shaded locations. Weevils: If leaves have notches in the outside edges, these are caused by weevils. Weevils spend the daytime in the ground and come out at night to feed.
What is killing my rhododendrons?
To begin with, excessive water kills about 75 percent of all rhododendrons purchased. Rhododendrons are fibrous, shallow rooted plants that need good drainage to perform well. The drainage is typically excellent. Another cause of rhododendron death is lack of water.
Is Neem oil safe for rhododendrons?
Spraying a band of neem oil around the base of plants such as hydrangeas and rhododendrons will also assist in controlling slugs, snails and weevils. I have used neem oil successfully to control anthracnose and powdery mildew on dogwoods, lilacs and deciduous azaleas.
What kind of fertilizer do rhododendrons need?
At planting time, use 10-10-6 fertilizer before you water the plant in. In early spring, the rhododendron buds swell. At this time, apply a complete 10-8-6 fertilizer. Apply another light dose of this fertilizer when the leaves emerge.
How often should rhododendrons be watered?
Rhododendrons are shallow-rooted plants that require water twice per week during the first growing season. Once plants are established, though, you should only have to water during dry periods (2 to 3 weeks without rain).
Why are rhododendrons dying?
Anyone who has ever been to the several locations around the world where rhododendrons originate knows that rhododendrons grow in shallow beds of highly organic matter. The drainage is typically excellent. Another cause of rhododendron death is lack of water. Rhododendrons do not have taproots like trees: their roots grow very near the surface.
Why is my Azalea turning yellow?
Phytophthora root rot causes the azalea’s leaves to turn yellow but the veins to remain green. The leaves will begin to rapidly fall from the shrub. Once the leaves drop off a branch it dies completely until the entire shrub perishes. Roots take on a reddish-brown appearance.
What is eating my Rhododendron?
Weevils are one of the most common and destructive rhododendron pests. The insects eat the leaves of the plant, weakening it and eventually killing it. Weevils live in leaf litter on the ground and climb rhododendrons at night to feed.
When to plant rhododendrons?
When to Plant Rhododendron. Plant the rhododendron bush in spring when danger of frost has passed. Plant the bush high in properly prepared soil, as soggy and waterlogged roots are the main cause of plant failure in the landscape.