Question
Hello,

I planted 18 arborvitae bushes 5 footers this summer. Several of them seem to be having a difficult time and are turning brown. I have put the hose on them thinking they were not getting enough water and when I use a moisture meter on them about a foot long they read all the way to wet. Not sure what to do?

Thank you

Answer
Hi there. Here are a couple possibilities.
The care of the trees at the nursery can play a big role in survival. How long were they dug before you bought them?
Did they get watered properly while the nursery had them?
You may be over-watering.
As spring turns to summer, your trees could need some special TLC. Young, newly-planted trees require attention like newborn infants, but don抰 overlook the needs of your mature trees either.

In many parts of the country, a summer drought is something gardeners and landscapers have come to expect, and even a mild drought can have a detrimental effect on young trees.

Use a dowel rod inserted into a root ball to monitor soil moisture. That homemade tool provided success for customers who did their own irrigating. Its my preferred method too. Saw 1/4" - 1/2 " diameter wood dowels into 12" to 14" lengths, sharpen an end, and insert one, two or three of these into a root ball.
The sticks are left in place, and pulled out every day or two, to see if the wood surface is moist or dry, indicating the presence or absence of moisture. This method can be more practical than trying to monkey-around with moisture meters, especially since the soil textures in root balls vary from clay to porous compost. Moisture meters can work too, but consider the dowel method as a good alternative.
The sharpened dowel method is an inexpensive and reliable means to check the concealed area within a root ball. As long as the stick still fits tight, try and use the same holes each time. This limits probing in the root zone - an insignificant effect on the roots.
One extra benefit of the dowels, is lack of malfunction (if they don't break). What do you do if your moisture meter malfunctions ? How would you know if its defective? That's the best part about dowels. They tell the truth about the moisture. That stick will be moist, or it will be dry.
You will need to estimate whether the stick is moist, or whether it is wet; like saturated. A moist root ball is preferred, but not a water-logged root ball. If there is too much water in the root zone or planting hole, oxygen for the roots may be limited.
In fact, a moisture meter could be used with the dowels, but I see no need. It's not hard to tell if a wood dowel is dry, a little bit dry, moist or saturated.
Also, a dowel can reach deeper than a finger. For small plants, shorter probes are needed. If a tree has a taller root ball, wooden moisture probes can be longer, like 18" or longer.


How much water does a young tree need? A good rule of thumb is the equivalent of about one inch of rainfall a week. If you don抰 own a rain gauge, local news sources often provide information about current rainfall conditions, and you can compensate for shortfalls simply by watering.

You might be surprised to know how much water you will need to provide. A brief sprinkle isn抰 going to cut it!
Hope this helps,Bill