Winter Protection For Boxwood

Detroit-Garden-Works.jpgBoxwood is one of the most versatile and robust growing evergreens available for planting in my zone. There are a number of great cultivars.  Green Velvet matures at 3′ by 3′, and keeps its great color all winter. Green Mountain is virtually identical to Green Velvet, but grows to 4′ tall by 3′ wide. Buxus microphylla koreana, pictured above, is hardy in this full south sun location, and can grow to 5′ by 5′.  The winter color is a dull orangy bronze. Winter Gem boxwood is incredibly hardy, and grows slowly to about 4′ by 4′. The leaves are smaller, and narrower than Green Velvet.

DSC_4001There are lots of other hybrids available.  Vardar Valley is an outstanding hardy cultivar of buxus sempervirens. It matures at 1′ to 2′.  The leaves have a distinctive blue green color.  As it is a slow growing variety, it is not routinely offered for sale at local nurseries.  Most of the boxwood sold in my area is grown in regions where the season is long enough to permit 2 flushes of growth per season.  This means nursery can get a salable product faster.  Boxwood is graded by width-not by height.  A boxwood takes about 7 years to grow to an 18″-24″ size.  This makes them relatively expensive to buy, compared to other ornamental shrubs that grow quickly.

MG 2013 (29)Boxwood is indeed a versatile shrub. They make great hedges, as their growth is uniform, and they are very tolerant of pruning.  That tolerance makes them an ideal subject for living sculpture. Boxwood pruned into spheres, squares, cones and cylinders are striking and delightful.  The large boxwood in this landscape will be kept pruned in spheres.  The small boxwood will be allowed to grow together, and will be pruned flat. This garden will have a much different look in a few years. All of these boxwood are Winter Gem.  The fine textured foliage makes them ideal for pruning into a formal, strictly geometric shape.   DSC_1801Boxwood are quite friendly to other plants.  Provided care is taken in the selection of a cultivar for a specific site, they will stay in bounds. These boxwood rectangles are a beautiful foil for the clipped espaliered crab apples. If the face is pruned on a very slight angle out from top to the bottom, they will stay green all the way to the ground. A boxwood which is hard pruned into a specific shape will stay green on the interior.

boxwood-green-velvet.jpgBoxwood makes a fine tall ground cover under a tree.  They are quite shade tolerant. A small landscape such as this is all the more interesting for a change of level.  These boxwood are a welcome visual intermediary between the ground plane, and a linden which has grown to substantial size. That they are shade tolerant means they can be sited in lots of places.  Naturally grown boxwood make a lovely backdrop for ferns, hostas and shade tolerant perennials.  A boxwood provides a green backdrop for the earliest of perennials to appear in the spring.  The small textured foliage makes them a great companion for the bigger textured hellebores, and European ginger.

Aug 31 2013 (20)A boxwood would go so far to oblige a gardener who wishes to grow them in containers.  They do need large enough containers so there is room to grow.  The root ball of a decent sized and well grown boxwood might be larger in diameter that its leafy component.  Boxwood in containers need special attention to proper watering. They need to be well watered prior to freezing weather.  They will rely on water stored in the stems and leaves to survive they winter, as the water in the container cannot be absorbed when it is frozen.  Boxwood in ground has much more widespread moisture available to its roots, especially given how long it takes for the ground to freeze to any significant depth.  A boxwood confined to a pot needs regular water.

boxwood-hedge.jpgPruning boxwood takes more than a good eye.  A great job invariably involved the setting of level lines.  Relatively level boxwood has a forlorn and unfinished look.  This boxwood has been pruned level with the horizon, even though the driveway drops down to the street.  The boxwood at the bottom of this drive is quite a bit taller than those plants at the top.  Level boxwood has a serene and solid look to it.

August 12 2013 (11)Boxwood can help provide structure to a garden.  This densely growing shrub provides a simple and strong contrast to the garden elements.  This pruning is loosely formal, and softens the stone wall behind them.

Aug 31 2013 (18)I have written about boxwood plenty of times before – I do like them.  It was painful to see how many boxwood in my area were severely damaged or killed outright by our last winter.  Some were crushed by the huge snow loads.  Others in more exposed locations were damaged by the extreme cold.  That cold, in conjunction with sun and wind burned the leaves. Leaves that were completely dessicated, died. It took the coming of the spring weather to see how terrible the damage truly was.  Some of the boxwood at the shop died outright.  The damaged portions will take years to recover.

July 5, 2012 035If you have ever hung a boxwood wreath on a shaded door for the winter, or used cut boxwood in winter pots, you know those stems will dry out, but stay green until the temperatures moderate.  Like many evergreens, by the time a boxwood shows signs of stress, it is too late to remedy the problem.  Now that fall is approaching, I would urge anyone with boxwood in my zone to spray them with an antidessicant.  An antidessicant is a waxy coating with will slow the evaporation of water from the leaves in the winter.

boxwood-spheres.jpgI have heard talk that this winter looks like it may be a very cold winter.  Something like last winter.  Though boxwood is hardy in this zone, extreme cold, sun, and drying winds can damage them.  Though a boxwood may grow out of winter burn, that look is unsightly come spring.  If your boxwood are 15 years old, it will be very expensive to replace dead plants with new plants of the size you already own.  Last winter was dramatic evidence that winter protection for boxwood is a good idea.  photo (43)I recommend Vapor Gard.  It is widely used as an agricultural antidessicant. The main ingredient is pinolene, a natural polymer made from pine pitch.  It can significantly reduce winter burn.  You can buy it, dilute it 1 part to 20 parts of water, and spray it on your boxwood. If you have lots of boxwood, your tree care company can spray this for you.  It is best done on a dry day, before the weather drops regularly into the low forties.  The polymer coating will protect those leaves over the winter, and help them retain moisture.  Vapor Gard is a natural and non toxic spray widely used on crops, including cherries.  It is an easy way to protect your investment. Do read the label-it is not appropriate for every and any plant. I plan to spray all of my boxwood with it soon; one application will protect them the entire winter. The boxwood pictured above from this past spring-heartbreaking.   Interested further?   http://www.cdms.net/LDat/ld06L002.pdf

Comments

  1. Deborah,
    Amazing pictures and thank you for sharing. I have a quick question and hopefully you can help. I planted several varieties of boxwoods in clay pots early this year and with winter coming on I am clueless as to whether I have to bring them in or not. The pots are old and not important, but I definitely don’t want to lose the plants. I applied an anti-desiccant a few weeks back and live in a zone 6 coastal area in NE Massachusetts. Any thoughts? Thanks in advance.
    Tony

  2. robert wills says:

    what amazing tops for boxwoods! thank you deborah.
    ok my turn to ask a question which is really just a confirmation of all answers above so in our case Deborah, which is three beautiful boxwoods in plastic pots that adorn our pool area, would it be correct to say :
    -water Now liberallly, then, spray them with vapor guard, no need to wrap in burlap, and park them in the unheated cabana for the winter?
    bonus question: dont they need some sunlight during the winter OR are they completely dormant?

    • Deborah Silver says:

      Dear Robert, you have a good plan in mind. But if the winter is exceptionally bitter cold,as it was for us several years ago, even the protection of an unheated building was not enough – we lost some. Mostly non-hardy varieties.Their roots were still above ground. I have a few clients who have boxwood in pots for the summer. We plant them in the ground in a protected spot for the winter, soak them thoroughly, and vapor gard them. No, they do not need light for the winter. hope this helps. best, Deborah

      • robert wills says:

        thanks deborah! i just dont have it in me to plant these boxwoods for the winter. i will roll the dice in the cabana with them. you have been exceptionally helpful and insightful where others were not, i will let you know how they fare during our mild Canadian winter! Rob

  3. Hi Deborah:
    I was admiring your buxus photos and am creating some plant tags for our nursery here in Canada. I was wondering if I am able to use your photos? I would send you proofs before we go to press.
    Looking forward to hearing back from you.
    Regards
    Rob – Pan Am

  4. Hi, I just bought/rescued the last Winter Gem Boxwood (Buxus microphylla) at a local Home Depot (3.7Gal pot, for $3.00) It appears robust and the top leaves are just turning golden. We just went through a hearty snow and freeze over the last few days (I live in Chicago) and I was wondering if I can care for this inside until spring. I am afraid that at this late time in the year, if I plant it, it will not survive the winter.
    I am a novice so any assistance provided would truly be appreciated. This is truly a beautiful evergreen and I hope to enjoy it for years to come.

    • Deborah Silver says:

      Dear Dave, you cannot keep boxwood indoors. If you can get it in the ground (next week you should have milder temps)spray it with an antidessicant like wiltpruf, and burlap it against winter winds. Be sure you water it thoroughly. Good luck, Deborah

  5. I appreciated this site very much. I have two nice boxwood shrubs in beautiful large concrete planters. This will be their first winter. I hate having to dig them out. I am going to keep watering as much as possible and cover with burlap and hope for the best in the spring. We do have some bad winters here in the northeast (NY) — any other suggestions? Cannot afford to buy gallon of spray for just 2 shrubs.

  6. Rachel Kohn says:

    I’m reading this advice too late in regard to spraying my boxwood for winter protection. We were considering covering our small boxwood bushes with styrofoam covers as they are right below our roof line and we often need to clear the roof of snow during the winter (Wisconsin) and we don’t want the weight of the snow destroying the bushes. Having them covered can protect them from snow, wind and temperatures but what about winter sunlight? They wouldn’t be the prettiest things, either, but would blend in with the snow as they are white.
    Thanks!
    Rachel

    • Deborah Silver says:

      Dear Rachel if you have snow like we do, it would break a piece of styrofoam.If you shovel snow off the roof, you may need sheets of exterior plywood. What does your local nursery recommend? best, Deborah

  7. Debra Lenzen says:

    Hi Deborah

    Do you know where I can purchase Vapor Gard? Thanks!

    • Deborah Silver says:

      Dear Debra, buy Vapor Gard if you have a lot of boxwood to do. It is only sold by the gallon – Hortmark is a distributor. For small numbers of boxwood, Wilt Stop by Bonide is available in smaller and ready mixed amounts. Garden centers carry it. Best, Deborah

  8. I am a boxwood newbie and just bought 2 small boxwood (winter gem and dwarf english) and would like to grow in containers in Philadelphia, PA area. They are still in their nursery pots, but was planning on moving to large plastic planters and letting them winter next to the house out of the wind. someone mentioned wrapping them in plastic. Now wondering if I should put in garage or basement instead of outside, leave in original pots or go ahead and plant in containers? Another person recommended putting a box over them to keep heat in…help!
    thanks

  9. Sue Brandon says:

    Dear Deborah,

    I live along the coast of Rhode Island and we have had trouble with boxwoods due to the cold temperatures as well as boxwood blight. I have found Ilex crenata compacta Hoogendoorn to be an acceptable substitute. It can take hard pruning and in our case, can withstand the cold humid air off the water.
    Good luck,
    Sue

  10. Roger Boeve says:

    In Virginia, the winter weather is not our primary concern. It is Boxwood Bliglht, a disease for which there is no cure. I’ve removed over 100 boxwoods and many fear that all the old boxwoods on the plantations around Richmond are at risk. What a shame. This disease is moving across the U. S. Sorry to be the bearer of bad news.

    • Deborah Silver says:

      Dear Roger, I dread the thought of that blight. I am so hoping that someone will discover a treatment-soon. I am so sorry you have lost so many. Deborah

  11. Starr Foster says:

    Wow. Best thing I’ve ever read about boxwood. You are truly an expert who has learned from vast experience, not just books. And is also timely, as I need to rehab a BW hedge. Love the gorgeous photos. Many thanks, Professor Silver!!

  12. joyce koreman says:

    Deborah,

    Many thanks for this information about Vapor Gard. Usually, because of the wind, we construct a fabric protection as tall as the boxwood. But along the front walk we think we might need this
    on both sides, and that isn’t pleasant to walk past for all our winter months. My gardener’s heart
    would be crushed if we lost our design to our winter cold. I don’t know why we missed knowing
    about Vapor Gard.

    And about the roses: what can I do this year. Most of my roses didn’t survive last winter’s cold.
    But for the beauties left what can we do?

    This is a wonderful site, and I appreciate being able to write you a note.

    Joyce Koreman
    48304

    • Deborah Silver says:

      Dear Joyce, I would read the Vapor Gard label, and see if it is approved for roses. If it is, what could it hurt? You just need to pick a day to mspray when there is no rain, so the film has a chance to dry. Best, Deborah

  13. Alison Wilson says:

    Dear Deborah:

    Many thanks for the advance instructions useful in protection of boxwood hedges. What is your opinion on burlap protection and/or additional mulch coverage. If the predictions are correct, we had better hunker down and hold on for a tough ride.
    Thanks,
    A.

    • Deborah Silver says:

      Dear Alison, burlap does help keep salt spray off of boxwood. Winter protection depends on where the boxwood are sited. I did not protect my boxwood at home at all, and I had no winter damage. They are sited in a protected location. I hate the look of burlap,so if I am trying to protect them from drying winds and cold, I prefer Vapor Gard. Extra mulch may just provide a cozy winter home for voles and other rodents-I would not do that. Best, Deborah

  14. Thanks for another timely post, Deborah. A question as to transplanting boxwood: for your zone if you have to or plan to, do you transplant in the spring or the fall?

    • Deborah Silver says:

      Greg, If I am digging up and moving, I would wait until spring if I could. If I am planting new plants with undisturbed boxwood, I could plant now in a protected location, and spray. That said, you would have to make your own call for yourself. Best, Deborah

Leave a Comment

*