Thursday, January 21, 2010

Cold weather shrubs, oaks & syrup

Question: One of my shrubs looks like it has been killed by the cold weather. I thought it was hardy. May I take it back for a refund?

Answer: Cold hardiness is not an exact science, and there are numerous factors that come into play when considering how cold hardy a plant is. A plant may survive 0 degrees F. for one night with no damage provided temperatures rise the next day. The same plant may be killed outright if exposed to only 15 degrees F. for three nights if daytime temperatures don’t rise above freezing. Plants that are well established are less likely to be damaged than those planted more recently. Cold snaps that follow extremely warm periods are more damaging than those that come after a gradual period of cooling. Plants that are flushed with new growth due to lots of water and nitrogen fertilizer are also more likely to be damaged than those grown under leaner conditions. Plants in pots and containers are much more susceptible to cold damage because their roots are more exposed than those of plants in the ground. Some evergreen plants in sunny areas will experience “leaf burn” if the ground remains frozen for extended periods. This is because the sunlight will raise the temperature of the leaf and cause it to transpire and lose water. The plant is unable to absorb water from the frozen ground which leads to the scorched appearance of the leaves. These plants often re-leaf in the spring with no major damage. This may be the kind of damage you are seeing, and it is premature to write the shrub off as dead. It is also unfair to expect a nursery to predict every possible scenario and guarantee success in all situations and conditions. If we are that demanding, it may lead to nurseries carrying only Japanese honeysuckle and Chinese privet.

Q: What is the difference between molasses and sorghum?

A: Sorghum and molasses are both syrupy products with similar textures, but are derived from different plants. Sorghum comes from juice of the sorghum plant that is boiled down. Molasses is a by-product of sugar production and comes from the sugarcane plant. During the production of sugar, juices from the sugarcane plant are extracted and boiled down to create the crystallized form of sugar commonly sold in stores. As this crystallized version is created, the remainder of the solution forms what is known as molasses. Depending on how many times the sugarcane juice has been boiled, molasses will have a different color, taste and texture.

Q: What kind of bay is used in cooking?

A: The bay used in cooking is Laurus nobilis. It is also known as “sweet bay” or “bay laurel.” Do not confuse it with other plants with similar names that may be unsuitable or even toxic.

Q: I have two identical oaks in my yard. However, one sheds its leaves early in the fall while the other one holds its leaves almost until winter. What can be the reason?

A: Genetic variability between the trees is probably the main reason. Oaks, even within the same species, have an especially wide range of characteristics. Oaks also hybridize freely. Your trees may look identical, but one may be a hybrid with another oak species, and this could be the reason one retains its leaves longer than the other. Location could be another less important factor involved. A tree in a protected location, over a water line or sewage line or near a source of artificial light at night will retain its leaves longer than normal.

Consumer Q’s
Prepared by the Office of Public Affairs
Georgia Department of Agriculture
Tommy Irvin, Commissioner

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