Box is typically English and an extremely popular plant for creating hedging and topiary. With regular tight clipping, it can retain an almost perfect formality year after year in whatever shape you choose to clip it. It is however also susceptible to a number of pests and diseases, including the dreaded Box Blight caused by two fungi, Cylindrocladium buxicola and Volutella buxi, Box Blight is an airborne fungal disease that attacks the leaves and stems. If left untreated it can result in dieback and bare patches and can quickly spread to other Box plants nearby.
Box Blight is an airborne fungus; therefore the spread of spores are primarily through water droplets carried by the wind. However, because the spores are sticky, it is possible for Box Blight to be spread by birds, insects, people and in particular, garden tools. Once spread, more spores are produced and they can survive drought, are unaffected by frost and remain viable for extended periods of time. For example, spores are produced in the spring yet viable spores can still be found in decomposing leaves after almost a year.
It is very easy to miss the early stages of Box Blight; often the disease will not be detected until parts of the Box plant dies and you notice significant leaf fall in your garden. However, there are a few symptoms to look out for. Early infection results in a general darkening of the leaves, which spreads until whole leaf is discoloured. By this time the fungus will have spread to the stem, resulting in dark lesions in the stem and the death of the leaf.
As a widespread, airborne fungal disease, there are no specific Box Blight fungicides on the market that have been proven to be effective. However, there are measures you can take to reduce the possibility of serious infection in your garden:
· When buying Box plants from a garden centre or other commercial source, keep them in isolation for a minimum of three weeks before planting to ensure that any suppressed disease is discovered before it can affect existing, mature plants.
· Avoid planting Box in damp, shaded, poorly ventilated areas as these are conditions Box Blight thrives in. Avoid overhead irrigation at all costs as spores are most commonly spread in water droplets.
· Regularly clean your garden tools, in particular your clippers and shears to avoid the transfer of spores. You can dip tools in diluted household disinfectants or bleach.
· Remove any dead leaves and foliage to minimise the chances of resting spores releasing the infection.
· If disease does break out, remove and destroy the infected plants.
Alternatives to Box Hedging
There are not many alternatives to this quintessential English hedging plant but one that is increasing in popularity is Euonymus japonicas Microphyllus. With deep green, dense foliage this compact plant gives a beautiful, formal appearance with minimal trimming. It is tolerant of many conditions including heat, poor soils and salt spray. A good container specimen, it is perfect for a low hedge, parterre or border.
It is easily grown in well-drained soils and is best with full sun in humid areas. Follow a regular watering schedule during the first growing season to establish a deep, extensive root system. Apply a general purpose fertlizer before new growth begins in ths Spring. Shear annually for a neat appearance. Pruning time: Spring after flowering.
It can also be clipped and trained into cone shapes or spheres just like Buxus sempervirens.
Another alternative to Box is Ilex Crenata. Whist being a member of the Holly family, the leaf is all but identical to traditional Box and is certainly not prickly! Growth habit is also similar to traditional Box hedging, though it does have several added benefits in that it is not prone to leaf scorch when it is pruned and that it will also break fresh growth from 'brown wood' - so if more zealous pruning is required and you cut into areas of bare stem new growth will appear.
Most importantly it does not suffer from Leaf Spot, Rust or Box Blight. This plant is so versatile - it can be grown into a lovely evergreen hedge up to 12 feet (3.5 metres) tall or can be kept trimmed short and tidy for the traditional potager edging effect. Alternatively it is perfect for topiary and can be trained and pruned into all sorts of shapes. If you decide to take this alternative option to Box the you should, under no circumstances, use any stimulants, fertiliser or bonemeal at planting time as such products will 'burn' any new root growth and slow down your plants development. Water thoroughly if the ground is dry. In extended dry periods ensure your plants are watered thoroughly at least once a week; this is even more critical on lighter soils. Trimming / pruning is best undertaken in May and September.