Saturday, December 18, 2010

Winterizing Evergreens-Anti-Desiccant Spray

Have you ever noticed scorched and browned foliage on certain broad-leaved evergreens after winter? Winter cold and winds can be harsh on your landscape. Evergreen trees and shrubs maintain foliage throughout the winter months where they continue to lose moisture. With winter temperature fluctuations, moisture loss and the ground still frozen, transpiration occurs from the needles and leaves increasing water demand. If the roots cannot keep up with these demands the needles and leaves start to turn brown and die.  Winter burn or desiccation is a dehydration of the plant due to water loss from the leaves through transpiration. This is caused by long dry periods of cold and thaw along with winter winds. Some broad-leaved evergreens such as holly, rhododendron, cherry laurel, skip laurel, mountain laurel, Japanese Skimmia, Osmanthus (False Holly), Leucothoe, Aucuba and Boxwood are even more susceptible to winter drying and long-term damage.  An easy way of avoiding winter damage to plants is to apply an anti-desiccant spray to the upper and lower parts of the foliage before the temperatures drop below freezing or during a winter thaw.


PLANTS PRONE TO WINTER BURN: broad-leaved evergreens such as Boxwood, Holly (examples include: Oakleaf Holly, Nellie Stevens Holly, Sky Pencil Holly, Hoogendorn, Northern Beauty, Steeds and other compact Holly), rhododendron, cherry laurel, skip laurel, mountain laurel, Japanese Skimmia, Osmanthus, Leucothoe, Aucuba, Southern Magnolia, Euonymus and Japanese Andromeda.

WHEN TO APPLY: Apply anti-desiccant when the daytime temperatures start falling below 50 degrees (Fall-late October/mid-November here in zone 7). Apply when the temperatures are above freezing and there is no threat of rain or frost within 24 hours. (This tip applies to areas going into their winter season-temperatures dropping below freezing: 0 degrees Celsius or 32 degrees Fahrenheit.) Anti-desiccants are organic and break down under heat and light so it is recommended to spray again in late winter if there is a prolonged winter thaw. The newer brands of anti-desiccant such as Wilt Stop and Transfilm are produced to last throughout winter with good coverage.

DANGERS: Be sure to read all directions on the label since anti-desiccants can cause photo toxicity on some narrow needled evergreens such as Arborvitae, Hinoki Cypress and Spruce that could cause more harm than winter burn.  Spraying in freezing temperatures will do harm to the plant.  Do not spray in freezing temperatures and allow time to dry before temperatures drop below 32oF or 0oC.

HOW OFTEN DOES IT NEED TO BE APPLIED: Sudden warm spells can trigger your evergreens to open their pores allowing for more water loss. If there is a winter thaw part way through the season it is recommended to re-spray your plants but only if the temperatures are to remain above freezing for at least 24 hours.

WHERE DO I PURCHASE ANTI-DESICCANT?: The most commonly used brands of anti-desiccant are Wilt-Stop and Transfilm that can be found in nurseries, garden centers or ordered online. Ask your landscape professional for more information.

HOW IT WORKS: Anti-desiccant spray is organic and biodegradable. It adds a protective waxy coating to the tops and undersides of the leaves of broad-leaved evergreens to help slow the process of transpiration which causes water loss and winter damage.

10 comments:

  1. Thank you for the informative post. I have had winter burn on my hollies over the years and was looking for how to remedy the problem. I tried the anti-desiccant spray and it seems to be working well. Thanks again!

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  2. As a fellow landscape blogger, I found your article to be very useful and have posted a link to it on my blog (http://bit.ly/vcejxY) and on Twitter @MoodscapesLLC!

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  3. melocnr@hotmail.comApril 26, 2013 at 8:02 PM

    I had some anti-desiccant solution that froze in the winter and has separated, is there something I can do to fix this??

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  4. It is oil based and what happened was that the oil separated out so my guess would be that shaking it vigorously would help to blend it back together. If all else fails and it does not blend then maybe buy some new.

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  5. Will Transfilm harm my Arborvitae? I can find nothing in the literature. Thank you.

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    1. Good question. Do not use Transfilm on Arborvitae or any fine needled evergreen. It will clog the pores so the tree cannot undergo photosynthesis/respiration. Anti-dessicant is meant for broad leaved evergreens such as Skip and Cherry Laurel, Holly and Boxwood that are prone to moisture loss due to a large surface area on the leaves.

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  6. Do I understand from your reply that anti desiccant should not be used on Hemlock or Spruce trees?

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    1. Correct. Anti-desiccant is meant for broad-leaved evergreens. On rare occasion I will hear of brand new trees being planted at construction sites in December and Transfilm being applied for protection but that is an unusual circumstance.

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  7. Also can you estimate pricing for a professional application of an anti desiccant on 43 trees? I'm worried that I've been overcharged and did not request an estimate. I'd like to be better prepared in the future. Thank you for your consideration of my question.

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    1. The cost depends on the area and size of the trees. I have an arborist who does quotes for me but it would be difficult for him to give an accurate quote without seeing the trees in person. I'd like to be of help but I wouldn't want to mislead you. It is good that you got your trees sprayed, especially if you are having the type of winter we are.

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