Question

Practical – Site Visit • Home Site Visit February 6, 2014 • We investigated the hedge of east side of property that was showing signs of distress. The edge has Podocarpus and Arborvitae planted together. Symptoms are green tips with older or lower leaves brown and dead. Shrubs have been replaced several times. We checked the irrigation time clock and learned that it is set to water the yard on Monday, Wednesday, Friday, Saturday, and Sunday at 12 noon for 12 minutes per zone.

questions:

Answer 1

Q1- Yes it is a common problem. The leaves of these shrubs turn brown mainly in summer due to the heat, and is mainly because of drought conditions. When this happens in spring/winter, which is the case here, since the observations are made in the month of February, the reasons are the combination of wind, sun, freezing temperatures, and lack of available water in winter that can cause arborvitae and podocarpus foliage to turn brown. This happens because they are drying out. Water is the lifeblood of foliage. When an evergreen shrub cannot draw water up through its root system to its leaves during periods when the ground is frozen i.e. when any moisture in the soil becomes unavailable, those leaves, already beset by challenging conditions, give up their green color. This may also be referred to as a winter burn.

In order to prevent the browning of leaves, the following preventive measures can be taken.

• Select a sheltered location at planting time, since outdoors may get extremely harsh, depending on the region.
• Water in late fall. One reason why the leaves are turning brown here is due to the time and duration at which the plants are being watered. Sun is an enemy of the plant in winters. At 12 pm, the winter along with heat from the sun might make it extremely difficult for the plant to soak water. Try watering in the latter part of the day.
• Water during thaws. If winters in the region where these plants are located is too harsh, it may lead to freezing of the ground. The water will reach the plants only during the thawing periods, which may be in January or February. You can take advantage of this period and water the plants to ensure that it would reach the roots.
• Mulch over the root zone. Another way to prevent drying of the leaves is by mulching the roots, This would help in retaining moisture around the roots by conserving moisture in the soil.
• Protect with tree wrap. Regardless of the type of arborvitae or Podocarpus you plant, your best bet for avoiding winter burn is to wrap it in burlap. Placement in the landscape can also help prevent browning.
• Prune the branches as and when required.

The plant name and symptoms, description of plant setting, data and next steps are observation dependent. You must write it depending on what you witnessed at the site.