Designing a garden to reduce box blight impact
Box blight may never appear in your garden. However, in case it does, there are a few simple planting considerations that will make it easier to isolate and manage.
Nothing is quite like box (Buxus spp.). No matter whether you have a few balls or topiaries, a parterre or two, or a garden based on it, box adds a structure than no other plants can quite match. With its naturally dense and rounded growth habit, box can be used in many ways and can find a place in any garden.
Of course, the delights of box go out the window if an outbreak of box blight results in unsightly bare patches. Box blight can be difficult to manage once it is found in a garden and forward planning should start with elements of garden design. Whether designing a garden from scratch, or making changes here or there, it is important to consider whether to grow box, where and how to grow it and what cultivars to choose.
Decide how much box to plant
Only grow as much box as you can manage.
Choose less susceptible box cultivars where possible
Cylindrocladium buxicola attacks most Buxus species. Other plants in the Buxaceae family, such as Pachysandra terminalis and Sarcococca species, are somewhat susceptible.
- Buxus species and cultivars differ in susceptibility to box blight, although none are highly resistant
- Common box and the dwarf form B. sempervirens 'Suffruticosa' (popular for parterres) are very susceptible
- In general the varieties of B. microphylla are less susceptible than varieties of B. sempervirens
- Based on work done in Belgium, cultivars ‘Faulkner’, ‘John Baldwin’, 'Belvédère', 'Rococo', 'National' and 'Trompenburg' are less susceptible to the disease. Of these, only ‘Faulkner’ is readily available in the UK at this time
Consider alternatives to box in situations that favour box blight
There are many alternatives to box which could be considered in high risk situations, including where infected plants have been removed. You may decide to avoid hedging altogether in such situations, but the following all have small leaves and can be clipped into formal hedging styles:
Create spaces between box plantings
- Avoid a continuous ‘pathway’ (e.g. a very long hedge) of box that the pathogen may move along
- Separation of box plantings with, for example, stretches of lawn or other plantings makes it easier to manage them as separate blocks
- Avoid surrounding box topiaries with box hedges
Plant box in well ventilated areas
Box blight thrives in shady, damp areas so avoiding these conditions will reduce risk.
- Choose areas that have good airflow so that leaves are unlikely to remain wet for long periods
- Create and maintain space around the box. Crowding out the box with surrounding plantings will reduce airflow and increase humidity. Watch out for rapid growth of perennials in spring or fast-growing neighbouring shrubs
- Spacing plants a little further apart will improve air circulcation (30-40cm (1ft-16in) apart for B. sempervirens; 10-15cm (4-6in) for the more compact B. ‘Suffruticosa’)
- Avoid planting in areas with overhead watering. Drip irrigation will result in less leaf wetness
Minimise contact with box plants
- Minimising human contact will reduce the risk of arrival or spread
- Place topiaries and balls where they are not easily brushed past or handled especially in areas with frequent visitors
- Where box hedges will line paths, increasing the width of the path reduces the amount of physical contact and increases airflow