deer
Deer eat rhododendrons and azaleas, so protect your plants with fencing if they are a problem in your area.
why is my rhododendron dying?
The most common causes are poor drainage leading to waterlogging and root rot, under watering or severe cold. Other reasons may be that the soil is not acidic enough, or that the plant has been over-fertilised.
why is my rhododendron not flowering?
Lack of water is a common cause, as is lack of nutrients, particularly potassium which helps with flower formation. Your plant may also have been pruned at the wrong time of year, removing flower buds. If pruning is necessary, do it just after flowering in early/mid-summer so buds have time to form for the following year.
why are my rhododendron leaves turning yellow?
This is most likely because the plant lacks iron because your soil lacks the necessary acidity. Changing soil acidity is not easy to do, so if this is the case, try growing your plants in pots using ericaceous peat-free compost.
why are my rhododendron leaves curling?
Curling leaves are usually a sign that the plant is trying to retain moisture, so it could be that your soil is too dry, or that cold winter winds are desiccating the leaves. In both cases, water well and apply a thick layer of acidic mulch around the plant’s crown. Be careful not to overwater though, as this can also lead to leaf curl.
rhododendron vine weevil
Vine weevil can damage rhododendrons, especially those grown in pots. Notched leaves are a symptom of the adult beetles feeding, but it is the larvae feeding on the roots that cause most damage. If you spot vine weevil grubs, repot plants removing as many larvae as possible, and encourage more wildlife into your garden – birds, frogs and toads all eat them. If an infestation is severe, apply nematodes into moist soils in August or September.
rhododendron bud blast
Rhododendron bud blast is a disease spread by leaf hoppers which turns buds brown and later black. Remove and destroy the buds as soon as you see symptoms.
rhododendron buds not opening
Your plant may have been damaged by frost, or may need more sun. Move it to a more sheltered space if you can, or protect with horticultural fleece or bracken stems in cold spells.
rhododendron leaves drooping
Rhododendrons need water, so keep your plants well watered in the growing season.
how to get rid of powdery mildew on rhododendrons
Powdery mildew – a fungal disease causing dry, dusty patches on deciduous azaleas and discoloured blotches on rhododendron leaves – can be an issue in dry periods or where plants are closely spaced. It is difficult to treat, but you can try to prevent it by spacing plantings to allow good air circulation; avoiding planting in heavily shaded areas and by choosing resistant varieties. At Perch Hill we use a homemade spray as a preventative. To make it, mix 1 tsp bicarbonate of soda, 1 tsp vegetable oil and 1 tsp soap (we use Uncle Tom’s natural soap) with 400ml water and pour into a spray bottle. Shake well and spray on leaves, including the undersides.
Rake and destroy affected leaves – do not add them to the compost.
rhododendron leaf gall
This is most common on azaleas where the leaves become pale and swollen and covered in white, dusty spores. If you spot this, remove and destroy the affected leaves promptly before the spores can spread.
rhododendron rust and other leaf spots
Spots on rhododendron leaves can be a sign of rust and other fungal diseases. We don’t recommend fungicides, so advise that you rake up and dispose of fallen leaves around the plant and mulch well with bark chippings. To avoid fungal diseases, choose resistant varieties and plant plants with adequate spacing so that air can circulate. It’s also a good idea to avoid overhead watering, and to water in the morning so that moisture does not sit on the leaves.
rhododendron honey fungus
Honey fungus is a serious fungal disease which requires drastic action. If you spot honey coloured toadstools around your plants and white fungal growth underneath the bark, dig up any affected plants removing as much of the roots and any rhizomorphs (black bootlace-like structures which spread the disease) as soon as possible. Dispose of the top 45cm of soil and avoid replanting in the same area for six months.
