Protecting Boxwoods From Winter Damage

At Lauren’s Garden Service we get this question a lot! How can we protect our boxwoods from winter damage? Some say to wrap the shrubs in burlap- is this helpful? Boxwoods add a unique, formal, elegant look to a garden. They are slow growers so if they become damaged they are expensive to replace. The variety of boxwood Buxus sempervirens ‘Suffruiticosa’ is very susceptible to disease. Some clients don’t like their stinky foliage smell. It can be frustrating to have a landscape FULL of boxwood hedges and have some of those plants die off. Because of the expense to replace the dead shrubs and the slow growing nature of boxwoods, I have avoided them a lot. What I’ve run into in the past are clients with old boxwoods that have grown too large for their location and have not been maintained by regular pruning. When I have tried to revive them it takes so many years to recover from a restorative pruning and sometimes it is unsuccessful. I’ve been worried about ruining old specimens. In some applications boxwoods can be a great choice (deer! shade!) and can be relatively low maintenance. They’ll still need some knowledge and care for success prior to planting and for winter care. The main questions I receive are about protecting boxwoods through the winter. This is an appropriate question because boxwoods, despite being called American and English, are actually from Eurasia where winters are mild.

Lets take a look at the factors that effect winter damage in boxwoods.

1.Previous Plant Stress   

If a boxwood shrub is already experiencing stress it will be more susceptible to winter damage. Some examples include poor drainage causing too much moisture in the root zone of the shrub. Inadequate watering during shrub establishment can allow the plants to dry out. Planting the shrub too low and covering the base of the shrub with mulch will also cause plant stress. The wrong pH (boxwoods like alkaline soil) can add to plant stress.  Has the shrub been planted in its appropriate location concerning soil and sun exposure? Is it a windy location? Has it been planted properly, fertilized properly, watered enough? Often once damage is seen it is too late to correct the issue.

2.Temperature Fluctuation

Boxwoods originate from locations with milder winters. Cooler temperatures than the plants are used to are one. What is more concerning is temperature fluctuation from warm to very cold and the other way around. When we have larger temperature fluctuations then a boxwood is more susceptible to winter burn or boxwood decline as it adds to the stress of the shrub.

3. Snow and Ice

Large amounts of snow and ice will damage many shrubs and trees. Boxwoods can be protected with burlap and twine or plastic wildlife netting. A small amount of snow can actually insulate the boxwoods from cold temps. Tying the shrubs together will help ensure that the larger amounts of snow will slide off of the shrub rather than crushing the branches.

Top 3 Boxwood Problems

  1. Winter Burn: Boxwoods are susceptible to winter burn because many of the species originate from areas that have milder winters. Winter burn is noticed as yellow, brown dead leaves on the outside of the bush. Often winter burn can be successfully pruned out the following spring and the shrub will be just fine. The cause is when the leaves dry out and the  ground is frozen so there isn’t any water accessible to the plant and the winter winds come. The best way to avoid this is the water the boxwoods appropriately throughout the year, including in the winter when the ground is not frozen. You can also apply a thicker layer of mulch under your boxwoods (just be careful not to cover the base stem of the plant with mulch) to help keep the soil moist. Your boxwoods will tolerate some winter burn from time to time. When the shrubs receive winter burn for several years in a row then the shrubs may not recover. You can spray the leaves with an antidessicant which coats the leaves with a waxy substance to help keep water in the plant. You can use Vapor Guard or Wilt Stop. Water boxwoods well and apply before temps decrease to 40 degrees regularly.
  2. Boxwood Decline- This disease is common in the so-called English  boxwood Buxus sempervirens ‘suffruticosa’. Once you have this in your garden it is common for it to spread to other boxwoods of the same variety. The soil also becomes infected so likely another boxwood put in the same location would succumb to the same disease. The best solution for boxwood decline is to replace the shrubs with species that are not susceptible. Justin Brouwers is a nice variety to replace suffruiticosa.
  3. Breakage- It is common for branches of boxwood shrubs to break under the pressure of a large snow. The traditional solution is to wrap the boxwood in burlap and twine. A more cost and time effective solution would be to wrap the boxwoods in plastic wildlife netting and twine.

Boxwood Solutions

Wrap in burlap or plastic wildlife netting to protect from breakage in a heavy snow.

Be sure to water appropriately the rest of the year and when the ground thaws and temps warm up to avoid winter burn. Consider using an antidessicant.

Use proper planting techniques to ensure boxwoods are not planted too deeply or covered at the base with mulch.

Apply mulch around the shrubs in the fall to help insulated moisture throughout the winter.

Apply lime to alkalize the soil around boxwood shrubs. Apply 1 inch of compost around the shrubs once a year.

When selecting plants for your garden be sure to select appropriate varieties of boxwood for your location. Plant plants in areas protected from winter wind and bright winter sun. Wintergreen is a nice cold hardy selection.

Here is a list of hardy boxwood varieties from an article in Rodale’s Organic Life called “Avoid the Boxwood Blight with Hardy Varieties” found here.

Small-Leaved Boxwood
Buxus microphylla

  • Grace Hendrick Phillips: very dwarf; 1 × 2 foot; zones 6–8
  • Compacta (Kingsville Dwarf): the smallest of them all, tiny leaves, dense, very slow; 1 × 1.5 foot; zones 6–8

Japanese Boxwood
Buxus microphylla var. japonica

  • Green Beauty: deep green, responds well to pruning, a good substitute for English box; 3 × 3 feet; zones 6–8
  • Morris Dwarf: slow, formal hedge for sun; 1 × 1 foot; zones 6–8
  • Morris Midget: very dwarf, small leaves, sun tolerant; 1 x 1 foot; zones 6–8
  • Wintergreen: cold-hardy, good for hedge, fast-growing; 4 × 4 feet; zones 5–8

Common or American Boxwood
Buxus sempervirens

  • B. sempervirens: called American boxwood, tall, tried and true species; 5 × 4 feet; zones 5–8
  • Dee Runk: upright fast growth; 8 x 2 feet; zones 6–8
  • Elegantissima: best variegated gray-green and cream, disease-resistant; 3 × 2.5 feet; zones 6–8
  • Fastigiata: bluish-green upright growth for hedge; 8 × 3 feet; zones 6–8
  • Graham Blandy: most narrow columnar, better in cold climates, may need tying or pruning; 7 × 1 feet; zones 5–6
  • Jensen: similar to English; 2 × 2 feet; zones 6–8
  • Newport Blue: globular, quite blue-green foliage; 4 × 3 feet; zones 6–8
  • Pyramidalis: upright cone; 8 × 4 feet; zones 6–8
  • Rotundifolia: fast growing, largest leaves, shade tolerant; 5  × 4 feet; zone 6
  • Vardar Valley: disease-resistant, bluish new growth, hardy; 1 × 3 feet; zones 5–8
  • Wanford Page: long-lasting chartreuse new growth then leaves mottled green and yellow, dwarf; 2 × 1.5 feet; zones 6–8

Korean Boxwood
Buxus sinica var. insularis (B. microphylla var. koreana)

  • Justin Brouwers: sun to shade, natural globe; 2 × 2 feet; zones 6–8
  • Nana: spreading dwarf with narrow leaves, chartreuse in spring, slow; 1 × 3 feet; zones 6–8

Hybrid Boxwood
Buxus hybrids

  • Glencoe: selected at Chicago Botanic Garden, container plant, edging, hardy; 4 × 5 feet; zones 4–8
  • Green Mound: sun to shade, globular, hardy; 2 × 2 feet; zones 4–8
  • Green Mountain: upright, conical, hardy; 4 × 3 feet; zones 4–8
  • Green Velvet: lime green spring growth, mounding, hardy, 2 × 2.5 feet; zones 4–8

 

We can help you with any of your garden needs from design, planting and building to regular garden maintenance, weeding, pruning, mulching, edging, fertilizer, etc. We also offer stone work services- our designer can draw up a nice plan for you and our team can install it! Call 410-461-2535 to schedule a free estimate or enter your info here and we’ll contact you! 

Lauren Turner, Owner-Lauren’s Garden Service, LLC