|Looking up at these trees, you can see|
that one is leaning dangerously.
Wednesday, November 28, 2012
Friday, November 16, 2012
One of the effects of Hurricane Sandy was coastal flooding. The result is that many areas of turf and trees have been either submerged in salt water or deluged with salt spray. While coastal plantings are usually salt-tolerant, many areas further inland have received a dose of salt that can be toxic to grass, plants and trees. The effect of salt is so damaging that it was used as a weapon in ancient times to destroy an enemy’s crops.
When the soil’s salt content increases, roots find it harder to take in water. At elevated salt levels, water within the root can actually be drawn out of the plant, causing wilting. Neither sodium nor chlorine is generally good for plants (trees take the small amount of chlorine they need from the atmosphere). The sodium will displace essential nutrients like potassium, calcium, and magnesium, making them unavailable to the plants. At the same time, the roots take in the chloride ions and transport them to the leaves, where they accumulate and interfere with chlorophyll production and photosynthesis.
|Grass damaged by sea salt|
“The solution to pollution is dilution” is an adage that is appropriate here. Since salt is water soluble, it can be further diluted and washed through the soil by adding more water. Water your turf and plantings until the soil can’t absorb any more, wait for it to drain completely, and then water again. Keep it up until the ground freezes.
If your Almstead turf specialist suspects that there is too much salt to be eliminated by dilution alone, he will probably test the soil to determine the level. If the salt level is too high, we usually add gypsum to the soil through core aeration. We also have organic amendments containing humates that can speed up the process. With early action, the effects of Sandy’s salt water bath should be mitigated by spring.
Friday, November 9, 2012
|Rhododendrons respond to cold weather.|
Many of you with rhododendrons in your yard can tell the temperature outside by looking at the droop of their leaves. Rhododendrons are highly thermotropic plants: their leaves move in response to the temperature. As the thermometer falls the leaves begin to droop and curl; when the temperature goes well below freezing, the leaves are tightly curled and pointing straight down.
It’s hard to believe that these leaves will unfurl and rise again in response to warmer weather – but shrubs and trees are remarkably resilient. There are times however, when they can use some extra help.
As winter approaches, I recommend applying antidesiccants (also called antitranspirants) to most broadleaf shrubs. This is not a remedy for the curling leaves of your rhododendron – those leaves are supposed to curl and actually help the plant survive the cold. The stomata (the tiny holes on leaves that allow the escape of moisture) are tightly closed, preventing any moisture loss. The problem for broadleaf evergreens is not the cold, but the warmth. When a winter thaw occurs, your rhododendron leaves will straighten out, rise up and start sweating (actually transpiring). Because of the frozen ground, the roots may not be able to replace this water loss. Add some chilly winds, and the moisture loss can be dramatic. This is where leaf damage and loss -- and even plant death – may occur.
The antidesiccant adds an additional oily or waxy coating to the leaves, keeping the moisture inside. Many evergreens in our area are especially vulnerable to winter damage, particularly holly, rhododendron, cherry laurel, skip laurel, mountain laurel, Japanese skimmia, leucothoe, aucuba and boxwood. I recommend using an antidessicant on these plants in early winter. We try to spray the plants with antidessicant on a dry day when there’ll be no precipitation and the temperature is above freezing (around 40 – 50 degrees is good); you shouldn't apply the spray in freezing temperatures. It's important to coat both the top and undersides of the leaves. Antidesiccants are typically organic and biodegradable; they will wear off the leaves by spring.
Rose canes and hydrangea stems will also benefit from the spray, as will young trees with thin bark. Some evergreens with needles do not need antidesiccants; plants like arborvitae and spruce can actually be harmed by it, or at least lose their blue color.
When a winter thaw occurs, as often happens in our area, another coat of antidesiccant will help the evergreens stay hydrated until spring.
-Ken Almstead, CEO and Arborist