Native Plants

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Friday - July 01, 2011

From: Austin, TX
Region: Southwest
Topic: Watering, Trees
Title: What fertlilizer for live oaks under drought conditions?
Answered by: Guy Thompson

QUESTION:

In your June 7 answer about helping live oaks survive the drought, you state that additional fertilization may help as well. What kind of fertilizer to you recommend and how should it be applied? Thanks.

ANSWER:

Tree specialists don't agree on a particular type of fertilizer, one recommending 13:13:13 (nitrogen:phosphorus:potassium), while others just say a "standard" fertilizer will suffice and still others do not mention fertilization under drought conditions. Mr. Smarty Plants suggests an organic nitrogen (slow-release) fertilizer such as 8:2:4. Follow the instructions on the package, but apply a fairly low amount of the fertilizer around the trees near their drip lines. Too much fertilizer could promote new leaf formation - not good in drought times. If the trees seem to be relatively healthy you might well delay applying the fertilizer until September, which is the normal time.

Make sure you don't use Weed-N-Feed fertilizer. This has a herbicide that kills broad-leaf plants, including oaks! Water the fertilizer in well after application. Hopefully there is some sort of mulch of leaves or other plant material on the soil to help retard water evaporation.