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Wednesday - March 04, 2009

From: Goodrich, TX
Region: Southwest
Topic: Wildlife Gardens, Trees
Title: Fertilizing oaks to produce more acorns
Answered by: Nan Hampton

QUESTION:

What type of fertilizer would I use on oak trees to possibly increase growth and acorn production ? I have some flooded oak timber that is home to migrating ducks but there is little for them to eat.

ANSWER:

There is a great deal of controversy about whether fertilizing oak trees influences their ability to produce more acorns. Indeed, there are some sources (e.g., Whitetail Stewards Inc.) that say not to waste your time and money fertilizing oaks since there are so many factors that can affect the amount of oak mast produced in any year—rainfall, genetics, general humidity, timing of late frosts, pest infestations, etc. Additionally, the production of large crops of acorns tends to be cyclic. Producing a heavy crop of acorns one year usually results in several years with a lower production. For red oaks this can be a 5-7 year cycle and for white oaks it may be a 3-5 year cycle. For a thorough discussion of the unpredictability of acorn crops see Improving acorn production - Part I: Factors affecting acorn production of oaks from Whitetail Stewards, Inc.

Most professionals seem to agree on at least one strategy for improving the amount of oak mast—that is to insure that the oaks that appear to be the best producers are not crowded. Trees around these high yield trees may need to be thinned so that they are not competing for sunlight and water. Outdoor Life has an informative article, Mast Production--In a Nutshell, that gives a short lesson in oak biology and how to manage them. The U.S. Forest Service North Central Forest Experiment Station has recommendations on How to Manage Oak Forests for Acorn Production.

If you still think you would like to fertilize your oaks, it certainly is not likely to harm them. What kind of fertilizer should you use? You can see in the answer to a previous question about fertilizing oaks, that recommendations from professional landscapers varies. Some say use a 'standard' fertilizer, while others recommend a 8-2-4 compost-based or a 5-10-5 mixture. (The numbers refer to percentages of nitrogen, phosporus, and potassium.)

In your flooded oak timber you could add other plants that could provide additional food for your migrating ducks. Here are some wetland plants that are used by ducks and other waterfowl for food and cover:

Grass/grasslike

Eleocharis montevidensis (sand spikerush), Scirpus cyperinus (woolgrass), Schoenoplectus robustus (sturdy bulrush)

Other aquatic or wetland plants

Duckweeds such as Lemna minor (common duckweed), Potamogeton nodosus (longleaf pondweed), Sagittaria graminea (grassy arrowhead), Pontederia cordata (pickerelweed)

You can find others in "Aquatic and Wetland Plants of the Western Gulf Coast" by Charles D. Stutzenbaker.