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Archive for February, 2015

A heavy snow shower blows into the valley on saturday creating near whiteout conditions. Photo taken by Melissa Jones.

A heavy snow squall with high winds blows into the valley on Saturday afternoon
briefly creating near whiteout conditions. Photo taken by Melissa Jones.

It’s very cold – for us, that is.

The high temperature for Fishersville, VA was only 11°F today. The low tonight is supposed to be four below with a wind chill of -8! Everyone in New England is probably laughing at me – considering this to be a heat wave compared to what they have been experiencing during this very cold winter.

Helleborus foetidus with its green bell-shaped flowers pokes up out of the snow.

Helleborus foetidus with its bright green
bell flowers pokes out of the snow.

Luckily, we have a bit of snow to insulate our plants during this frigid cold snap. It isn’t as much as we had hoped, but it will help. I know the vineyards in the area were hoping for at least a foot during this last storm. With the extreme cold that is now upon us, they were hoping to have a good snow cover to protect the grape vines. Unfortunately for them, the storm didn’t pan out as predicted. This was a light, fluffy snow that came down in fine, tiny flakes and accumulated very slowly. The totals in most places fell way below the 8″-12″ that was predicted. We only got 4.5″ at our house – but still, it was beautiful and it will provide some protection for the plants in our gardens.

Begonia grandis seed heads have already dropped their seed. Daffodil foliage pokes up in the background.

Begonia grandis seed heads. Daffodil
foliage pokes up in the background.

Snow has excellent insulating properties, especially when it is at least 10″ deep. The temperature under a deep snow pack is generally around 32 degrees even when the air temperature is below zero! I suppose this might be some consolation for those New Englanders who are buried under several feet of snow. They certainly have been hammered up there! Of course, with that much snow, many shrubs could be pretty flattened by the spring thaw! Here are some tips to help with that when the time comes.

Buddleia sprouts from roots.

This Buddleia died back completely
but came up from the roots.

Frigid temperatures without any snow cover can be very damaging to some of the trees and shrubs in the landscape. Those that are marginally hardy where you live are especially susceptible to winter damage and winter kill. I expect that there may be a lot of winter dieback on crape myrtles and butterfly bushes in our area after this winter. Get your pruning shears and pruning saw ready! Hopefully the roots will be protected underground. If the roots survive, new growth should pop up from below to form a new plant.

Luckily, the wind chill does NOT affect plants; only the actual air temperature. Wind chill only affects warm-blooded animals like us and our pets, farm animals, even the wild creatures like birds and mammals; critters that are trying to maintain a constant body temperature.

Winter burn on Nandina

Winter burn on this Nandina.

This is not to say that winter winds don’t affect our plants. What can harm the plants are the drying effects of the wind. The air in winter is very dry, as evidenced by our dry skin, chapped lips, and static electricity shocks! When the wind blows this cold, dry air over the plants, it carries precious moisture away from the surface of the plants. Evergreens, both broadleaf and needled, are especially affected because they continually lose water through their leaves during the winter; the wind accelerates moisture loss. When the soil is frozen or dry, it is hard for the plant to replace this water by uptake through the roots. This can result in winter damage and winter burn to leaves and even whole branches.

Rhododendron with tightly curled leaves. The flower bud is protected but heavy bud scales.

Rhododendron with tightly curled
leaves. The flower bud is protected by
heavy bud scales.

Rhododendron leaves droop down and curl up tight like little cigars when it is extremely cold. This is a reaction to the cold temperatures but there is still a debate as to why they curl. Read more about it – it’s pretty interesting!

One way to help protect your evergreens from wind burn and winter damage is to spray them with an anti-desiccant like Bonide Wilt Stop. Wilt Stop protects evergreens from winter injury by forming a soft, clear flexible film over the leaves. Wilt Stop also protects evergreens from salt damage which can occur when you have a hedge near a road where salt is spread during the winter. Apply according to the label directions.

Until next time – Happy Gardening and try to stay warm!

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Boxwood bronzing in winter

Orange is an interesting color for a boxwood!

Orange or bronze colored boxwood are common in winter but if you aren’t prepared for this color transition, it can be quite alarming to suddenly notice that your boxwood aren’t green any longer!

Several years ago, I wrote a post about this seasonal color change and it always receives a lot of views at this time of the year. The boxwood hedge at the nursery entrance is again sporting its orange and green winter coat. It is so interesting how the Korean boxwood turns orange but the other species of boxwood right beside it remains green throughout the winter.

Here’s the post from February 2012 …

We recently received an interesting question on our discussion board:

I’m curious to know what has caused the leaves on some of my boxwoods to turn orange during the past two months.

Here’s a snippet of the answer I wrote out to him:

“If exposed to full sun and frequent frost and wind, the foliage of some boxwood may become orange or bronze in the winter …”

Such a contrast between boxwood species

Such a dramatic contrast between
two different boxwood species.

This is really quite common especially in certain boxwood varieties such as the small-leaved Korean Boxwood (Buxus microphylla var. koreana).

In fact, the other morning when I was taking pictures in the Viette gardens, I noticed that the Korean boxwood in front of an outbuilding had a very definite orange/bronze tint while the boxwood right beside it, a different species but growing under the same conditions, was still a nice healthy green color. The contrast was striking and a neat display of the seasonal variation that can exist between two different species.

On the protected leeward side, the foliage remains green except towards the top where it is more exposed.

On the protected side, the foliage
remains green except towards the top
where it is more exposed.

Even more interesting is the fact that only one side of the Korean boxwood is showing the bronzing of the leaves; namely the side that faces west and is exposed to the prevailing winds and the sun. The side that faces the building (which is about 8 feet from the hedge) is still green except for some bronzing near the top where branch tips are more exposed. This provides pretty good evidence that the bronzing occurring here on this particular variety is due to the environmental effects of sun and wind. The building is definitely providing the boxwood with protection from the elements.

There are certain things you can do to help protect boxwood and other evergreens from sunburn and winter winds that might cause discoloration of the foliage.

The windward side has become bronzed from wind and sun exposure.

The windward side has become bronzed
from wind and sun exposure.

Most important is to keep them watered during the winter especially when the ground is not frozen. Gardeners often forget that evergreens continue to function physiologically (albeit at a reduced rate) throughout the winter. Cold winter winds can suck moisture from the leaves and if this water is not replaced through uptake by the roots, winter injury can occur. This is why it is important to water your evergreens deeply in the late fall before the ground freezes. During dry winter weather when the ground is not frozen, be sure to check your evergreen trees and shrubs and water deeply if necessary. This is especially important during a mild winter like we’ve been experiencing so far this year. The addition of a layer of mulch will help retain the soil moisture.

Boxwood bronzing

The small-leaved Korean boxwood
typically turns bronze in winter.

Feed your boxwood in the spring and again in the fall with a slow release organic fertilizer like Espoma Holly-tone or Plant-tone to keep them healthy and vigorous.

Spraying evergreens with an anti-desiccant like Bonide Wilt Stop will also help to protect them from winter injury by forming a soft, clear flexible film over the leaves. In colder areas, the more tender broadleaf evergreens like Camellias and some varieties of boxwood and hollies should be sprayed with Wilt Stop and then carefully wrapped in burlap for additional protection from sun and wind.

.

The answer, continued:

“The good news is, though many consider it unattractive, this bronzing will not kill the boxwood and they should green up again once temperatures warm up in the spring.”

Certain branches became more orange

A few branches became a brighter 
orange with no green remaining.

Personally, I think this winter “off-color” adds some interest to the boxwood – sort of like “fall color” in the winter! And keep in mind that for some boxwood like the Korean boxwood, this color change is normal during the winter months.

It is important to note that the overall bronzing of the foliage that I am talking about here is a seasonal discoloration, not winter kill. Winter kill is permanent and must be pruned out in the spring – but that’s another story …

Until next time – Happy Gardening!

Oh and Happy Groundhog Day!

 

Korean boxwood in early April has lost most of the bronze coloration

By early April the Korean boxwood had
lost most of the bronze coloration

A postscript to this post –

That same year (2012) on April 2nd, I took another photo of the same Korean boxwood. The foliage had almost completely transitioned back to its rich green color.

An amazing transformation!

Until next time –

      Happy Gardening!

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