The following was distributed at the 1995 Menninger Sunbelt Tree Conference By Roy A. Mecklenburg Fertilizer and Root Stimulant Applications

There is little or no benefit in applying fertilizer at transplanting, but in several months after transplanting, as new root growth occurs, nutrients will be absorbed and there can be a significant growth response. There is no evidence that fertilization at transplanting increases survival rates. There is no research evidence at this point that root stimulants, mycorrhiza, water absorbing polymers or gels will increase tree survival or growth rate after transplanting of landscape size trees. Research on seedlings indicates that mycorrhiza can enhance growth rates.

Nitrogen appears to be the primary nutrient which will stimulate tree growth in most soils. Total applications of fertilizer containing four lb. of N per 1000 sq. ft. appears to be adequate for the first growing season.

Length of Establishment Period
The establishment period is the length of time required for root re-growth to occur and for the tree to be able to survive on its own to the degree it was before being transplanted. This is the length of time that the tree will require special attention to insure survival and establishment. The tree establishment period in central Florida is 3 months per inch of trunk diameter for most trees. Slower growing or weak trees will take longer.

Larger trees will require more time, i.e. a 6 inch diameter tree will require a minimum of 18 months and a 10 inch diameter tree will require a minimum of 30 months.

Reference: Trees for Urban and Suburban Landscapes by Edward F. Gilman. Delmar Publishers, 3 Columbia
Circle, Box 15015, Albany, New York. 23323-5015. http://www.agriscience.delmar.com or 800-347-7707.