Issues With Rhododendrons Dealing With Rhododendron Insect Problems And Diseases

Issues with rhododendrons are rare as they are relatively low maintenance plants.
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Rhododendron Insect Problems

Spider mites – Spider mites feed off of bud and leaf sap, leaving leaves yellow or bronzed.
Lace bugs – If the upper sides of leaves are speckled green and yellow, then lace bugs may be at work.

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 diseases do rhododendrons get?

What are rhododendron diseases?

Bud blast (Seifertia azaleae)
Powdery mildew (Erysiphe spp.)
Petal blight (Ovulinia azaleae)
Azalea leaf gall (Exobasidium japonicum)
Leaf spots (predominantly Colletotrichum gloeosporioides, but occasionally other fungi)
Rust (Chrysomyxa rhododendri)

How do you fix a sick rhododendron?

Prune away any dying tissue. ...
Spray the leaves and stem of your rhododendron plant with insecticides. ...
Move your rhododendron if you think it may be getting direct afternoon sunlight. ...
Change your rhododendron's soil if you believe it retains too much water.

What insect eats rhododendron leaves?

The adult weevils chew the edges of the leaves, cut off the tips of needles, or devour entire needles (Figure J). The interior, older foliage is preferred to the terminal growth. Life History – Black vine weevils overwinter as mature larvae or as pupae.

Are coffee grounds good for rhododendrons?

Fresh Coffee Grounds for Acid-Loving Plants

Your acid-loving plants like hydrangeas, rhododendrons, azaleas, lily of the valley, blueberries, carrots, and radishes can get a boost from fresh grounds. ... Fresh coffee grounds still have most of their caffeine content as well as the acid.

How do you bring a rhododendron back to life?

Water the shrub at least two times a week just enough to soak the area around the root ball of the shrub. Lack of water results in brown leaf tips and the shrub looks like it is dying. Rhododendrons draw water from the leaf's tip first when it senses a water shortage.

Why is Rhododendron bad?

Potentially toxic chemicals, particularly 'free' phenols, and diterpenes, occur in significant quantities in the tissues of plants of Rhododendron species. Diterpenes, known as grayanotoxins, occur in the leaves, flowers and nectar of Rhododendrons. ... These toxins make Rhododendron unpalatable to most herbivores.

How do you keep a rhododendron healthy?

Avoid frost pockets and sites exposed to early morning sun.

Rhododendrons need moist but well-drained, acid soil between pH 5.0 and 6.0 that is rich in organic matter.
If you have alkaline soil, grow rhododendrons as container plants or see our page on more tolerant species and cultivars.

Are rhododendrons toxic?

The toxic component of rhododendrons and azaleas can be found in very high concentrations in honey made by bees that feed on them. ... Eating the leaves, nectar, or flowers of the plants can also lead to toxicity. Although rare, serious and life-threatening toxicity has occurred when people intentionally ate the plant.

What does an overwatered rhododendron look like?

Too Much Water Can Cause Curled Rhododendron Leaves

Because these shrubs have shallow roots, you won't have to dig too far to get a look at them. If the roots are mushy and black instead of firm and tan-colored, that means root rot has set in.

What is killing my rhododendrons?

Another cause of rhododendron death is lack of water. Rhododendrons do not have taproots like trees: their roots grow very near the surface. ... Frequently sunburned leaves are the result of the lack of water. For many varieties that have burned in the sun in the past, the cause was lack of water not too much sun.

Is Epsom salts good for rhododendrons?

Magnesium in the form of Epsom salts is sometimes recommended for rhododendrons. Magnesium is an essential element and lack of it will cause yellowish areas between the leaf veins on older leaves. If the leaves are a solid green the addition of Epsom salts would not be useful.

What causes brown leaves on rhododendron?

Cause Leaf scorch on rhododendrons is a response to stress. Water stress can occur under both extremes of flooded, overly-saturated soils or under drought conditions when too little water is present. Root or stem damage due to disease or transplant shock can also cause scorch symptoms.

What could be eating my rhododendron?

Deer and rabbits. Both these animals can cause great destruction in the rhododendron garden. We find Scottish rabbits can eat most evergreen azaleas and species deciduous azaleas such as R. albrechtii.

What is the best fertilizer for rhododendrons?

You'll want to use a particular fertilizer composition for the different stages of your rhododendron growth. 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.

Are eggshells good for rhododendrons?

Crush the shells with your hands, and sprinkle the powder near flowering bushes like rhododendrons and hydrangeas. ... Your plants will thrive from the calcium boost the eggshells provide.

Can you use Miracle Grow on rhododendrons?

How to Feed Rhododendrons. A month after planting, begin feeding rhododendrons with Miracle-Gro® Water Soluble Azalea, Camellia, Rhododendron Plant Food, which is specially formulated for acid-loving plants. For easy application, consider the Miracle-Gro® Garden Feeder, which lets you feed and water at the same time.

What is a good mulch for rhododendrons?

It is best to mulch with a 2-inch layer of an airy organic material such as wood chips, ground bark, pine needles, pine bark or rotted oak leaves. A year-round mulch will also provide natural nutrients and will help keep the soil cool and moist.

How do you know when a rhododendron is dying?

If it looks green or bright underneath, it's healthy; if it looks brown, the branch is probably dead. This winter and early spring were hard on rhododendrons, Brochu said, not so much because of the cold but because of wind, which dried out leaves until they were left brown and crumpled.

How do you perk up a rhododendron?

Treat lack of iron with a foliage spray of chelated iron according to the manufacturer's directions. Spray your rhododendron with 2 tablespoons of Epsom salts in 1 gallon of water if it is suffering from a lack of magnesium.

How hard can I cut back a rhododendron?

Follow the branch down to the last whorl of leaves you want to keep and cut just above those leaves, about 1/4 inch above the topmost leaf in this cluster. Large, overgrown rhododendrons can be cut 12-15 inches from the ground when necessary.