SUDDEN oak death is the snappy title which has been given to a devastating fungal disease attacking oaks and other native shrubs throughout North America.

Now Phytophthora ramorum, as it's more correctly known, has arrived in Britain but since it has not been attacking oaks no one is quite sure what to call it!

The horticultural press seems to have settled on ramorum dieback for the moment, not quite so snappy or so descriptive!

Mindful of the destruction caused by Dutch Elm disease, the Department for Environment, Food and Rural Affairs (DEFRA) has been taking this new threat to our trees and shrubs very seriously.

Plant health inspectors have been carrying out an extensive survey of nurseries, garden centres and public gardens, testing and destroying infected stock to prevent the spread of this potentially deadly disease.

Unfortunately, it's not easy to diagnose, having different symptoms in different species. So far, ramorum dieback has been found mostly on rhododendrons and viburnums, although it has also been identified on camellia, kalmia, pieris, syringa and yew.

On rhododendron, the fungus causes a twig and leaf blight, with a blackening of the leaf stalks, leaf base, mid-rib and tip. Twig infection may lead to sudden wilting of shoots.

On viburnums, pieris and camellia, symptoms are very similar, the disease causing wilting and ultimately death.

On yew, infection results in needle blight, affecting young foliage and leading to aerial dieback. Ramorum dieback operates at cool temperatures and is spread locally by rain splash, wind-driven rain and irrigation water. Long distance spread is by movement of contaminated plant material, growing media and soil on machinery, vehicles and footwear.

Personally, I don't think we have any need to panic about this disease just yet, although I will be checking regularly for symptoms on susceptible plants in the garden. If I were planning to plant any new rhododendrons or viburnums this winter (which I'm not), I would be tempted to isolate new specimens in a nursery bed for 12 months to make sure they were healthy. Phytophthora ramorum is a notifiable pathogen', if you think you have the disease on your premises, you are obliged to contact your nearest DEFRA Plant Health Inspector immediately.

Strange though it may seem, there are rhododendrons flowering now in the gardens at Brockhole. Rhododendron Yellow Hammer' flowers regularly in spring and again in most autumns. The flowers are small and pale, canary-yellow, showing up well amongst the dark green foliage.

In contrast, Rhododendron nobleanum has large trusses of rich pink flowers that are borne throughout the winter months. Sharp frosts will spoil the flowers of both plants, but in mild weather they look splendid, if slightly incongruous.

- Although the Visitor Centre at Brockhole is closed for the winter, the gardens and grounds are open every day of the year. A reduced admission price of 1 per car applies.

Jobs for the gardener

# Check stored apples regularly for signs of rot. Eat larger fruits first, the smaller ones will keep for longer.

# Pinch out the tops of autumn sown sweet peas when the shoots are more than three inches tall. This will encourage new shoots to come from the base.

# Protect any slightly tender plants from frost by tucking straw or bracken around the base. Cover the whole plant with horticultural fleece on nights when frost is forecast.