Nursery Notes by Mark Halcomb Release May 23, 2007

I feel compelled to continue writing about recovering our freeze damaged plants. I wish I could summarize it all very neatly. But I can’t. There is a lot of variation of damage between nurseries due to protection offered by tree lines, exposure to sunlight perhaps, north vs. south facing sloping fields, plant health or vigor April 6, low pockets where cold air settled, etc. Seedling plants have a natural variability that is not found in cultivars.

So, Zelkova is dead in one field and half dead in another. Some species of oak have busted bark in my nursery, but not yours. Terminal dieback varies greatly across the area of the same plant.

Look for damage in 4 places: terminal dieback, bark discoloration, bark busted on lower stem and at soil line and the roots of container plants.Bark discoloration should be checked in the upper portion and especially at the soil line.

A plant can recover from a light caramel (tan) color under the bark. A plant is not likely to survive a color darker than a medium brown. Medium is on the fence; it go either way depending on growing conditions. If and when the plant dies has to do with how soon and how severe additional stress is added to the plant. Irrigation would will greatly aid a plant with caramel or possibly a medium shade of brown.

Heavy suckering at the soil or on the lower stem is a definite sign that the tissue above the suckering is damaged, and that the plant is trying to survive. Trees with busted bark or heavy suckering should be cut back now.As low as you dare. Larger caliper plants generally have to be destroyed, because a quality plant can not be grown from a cut-back with a large stump. Cutting budded plants back is also very iffy. Boxwoods with busted bark need the damaged parts cut away. This may mean removing the top 12 inches or cutting them nearly to the ground.

I am concerned there are a few growers cutting away the upper damaged branch tissue and not realizing the damage goes much lower. But it is also possible that time has allowed the lower tissue to become darker or splits to occur. This is why we suggested to wait about pruning.

Pruning and light fertilization can now begin but excessive fertilization is considered a form of stress and harmful. If the spring fertilizer was applied, then there is no need to apply more at this time. If nothing has been done, apply 1/3 to ½ of what you normally would now. I see no reason to apply more later. We would definitely advise against applying dry fertilizer after July 1. Liquid can be applied up until Sept 15. Reasonably healthy plants that were fertilized early can be fertilized in mid to late June as normal. I have worked out rates per plant or row. Extension recommended rates are generally a third to half of the standard practice.This might be a good time to begin cutting back. I doubt that you will notice a difference in growth.

Brown roots are dead roots. Some container plants still look decent, but many of the outer roots are dead. Tear into the root ball to learn how many of the roots are alive.

With potential lost revenue and higher fuel costs, I would have to consider applying 1/3 to ½ of your normal fertilizer and mowing less frequently. But you have to decide what is best for your nursery. Appearance is important in some fields and competition for moisture must be considered. Weeds are never good.

There are so many variables to consider. I may be thinking of a different set of circumstances while writing this than what you have. Do not hesitate to call me at 931-473-8484 so you can get me on your page.

Keep your eyes open for individual plants that survived the freeze, especially seedling plants, unless they were in protected spots.

Obtain written permission from crop insurance companies before destroying plants. If you do not have crop ins. take plenty of good photos and visit your local FSA office to fill out a form.Let me know if it would hurt you financially to be unable to market Ligustrum sinense, L. vulgare, Lonicera maackii, L. morrowii, L x bella, Elaeagnus umbellata, E. pungens, mimosa, or multiflora rose.

May your rain gauge runneth over.

Comm/News/05-23-07 recovery summary

Mark A. HalcombUT Area Nursery SpecialistWarren Co. Extension201 Locust St., Suite #10McMinnville, Tenn. 37110mhalcomb@utk.edu931.473.8484 fax 931.473.8089