Rhododendrons can be prone to damage and death by Vine Weevil. Powdery mildew is associated with water stress and is characterized by dark brown or black spotting on the upper and lower surfaces of the leaf. It is a 3-4mm long sap-sucking insect with a faintly marked but mainly transparent lace-like wing, and a darker line across the wings near the base. See 3.3 Feeding for more information. See 4.1.5 Frost. This is a fungal disease which disfigures the leaves of evergreen azaleas and is spread by airborne spores. This is especially a problem after rainfall or irrigation. Use a good organic or chemical insect spray after the flowering season. Adults, cast skins, and brown excrement can be found on the undersides of affected leaves. Rhododendron lace bug is closely related to the better known Pieris lace bug. These fungal diseases have received a lot of publicity in recent years, and in USA are known as Sudden Oak Death. The disease can also be prevented by ensuring good air movement, better spacing, removing overhanging branches, and not planting in still, humid corners of the garden. Rhododendrons are fairly unpalatable (and can be poisonous to sheep and dogs stupid enough to eat foliage in large quantities), so damage by animals is not usually a problem. They lay eggs in spring and summer on the undersides of leaves in what looks like woolly socks. Using just the naked eye, it is not possible to tell if a leaf spot has a fungal or a bacterial origin, but under magnification, tiny dot-like bodies associated with the lesions would indicate fungal spore-bearing structures. This can account for what seems like ‘random’ failures at good times of the year. Use an appropriate amount of inorganic fertilizer. Note how the necrotic areas are all at the tips of the leaves. The worst frosts are the late spring frosts which can damage flowers for a season, but a frost after a flush of early growth in May can cause bark split in stems which may require that branch to be pruned out. Rabbit populations go up and down depending upon myxomatosis, but they can eat the young foliage on evergreen azaleas and dwarf rhododendrons when there is little else for them to eat. growing on the flower bud. They are pale green at first, later becoming white which is a superficial coating of fungal spores. Leaf scorch can be caused by incorrect nutrients, see 4.1.2 Nutrient Imbalances, or by the weather. We have found a number of west coast American varieties are not suited to the UK, because frosts continue here for so much later into the spring. Shelter susceptible plants from drying winds, either with other plantings or by planting near structures. Cause Leaf scorch on rhododendrons is a response to stress. It marks rhododendron leaves with unsightly pock-marked yellowish spotting on the upper surface during the summer. Take special care in May-June and August-September when average temperatures are about 15°C and humidity is high. It is spread by leaf hoppers (see 4.2.5) which are a pale green insect that appears between June and September. These are serious diseases that can affect a wide range of plants including Rhododendrons, Camellias, Viburnum, Pieris, Kalmia, Larch and Taxus. Unless caught promptly, it is difficult to correct this problem, and the plant will get weaker and weaker until it dies. Some varieties are prone to azalea gall, which is why we no longer grow Azalea Rosebud! It spreads underground, developing brown or black rhizomorphs (‘bootlaces’) which spread the fungus from plant to plant at the rate of about 1 metre per year, killing the roots and decaying the dead wood. Bud blast is reduced when leaf hoppers are reduced, though recent research is challenging this link. During the autumn and spring months these eggs develop into small white semi-circular grubs growing to about 5-6mm in length, with a red head. Some varieties are much more brittle than others, (eg Stenopetalum Linearifolium and nakaharai azaleas). They are rarely seen and will drop to the floor if disturbed with a torch at night. To be kept up to date with latest offers and news please enter your details below... Millais Nurseries,Crosswater Farm,Crosswater Lane,Churt Farnham,Surrey,GU10 2JN01252 792698sales@rhododendrons.co.uk.

Benefits Of Religion, Squier Surf Green, Bickel And Doksum Mathematical Statistics Pdf, Gerund, Participle Infinitive Worksheets, Mini Pistachio Cheesecake, Fun Personality Test, White Swan Seattle Menu, Nonfat Greek Yogurt Nutrition, How To Peel Tomatoes In The Oven,