The response to fertilization of newly planted trees, as well as established trees, appears to vary greatly depending on time since transplanting, species, soil type, climate, method of application, and type of fertilizer (Struve, 2002). Fertilizer recommendations for deciduous trees growing in loam or clay soils in temperate climates would not be expected to be appropriate for evergreen species growing in sandy soils in subtropical climates such as that of peninsular Florida. Relatively little research has been published on fertilizer requirements of trees in sandy soils of Florida and much of that has used chinese hibiscus (Hibiscus rosa-sinensis), a species that may be atypical for tropical and subtropical trees because of its high nitrogen (N) requirements (Broschat and Moore, 2010; Gilman, 1987, 1988).
Fertilizer requirements for trees during the first year after transplanting may be different from that of established trees. Gilman and Yeager (1990) did not notice significant differences in growth between fertilized and unfertilized laurel oak (Quercus laurifolia) during the short 17-month duration of their study. Gilman et al. (2000) also did not observe differences among treatments in the growth of southern magnolia (Magnolia grandiflora) during the first year after planting, but treatment differences were significant after 3 and 4 years. On the other hand, fertilized live oak (Quercus virginiana) were larger than unfertilized trees during their first year (Gilman et al., 2000).
Most fertilizer studies on trees have concentrated on N requirements, yet in Florida landscapes N deficiency symptoms are seldom observed. Magnesium deficiency is fairly common on Florida trees (Dickey, 1977), but it is not known if routine application of magnesium (Mg) or micronutrient-containing fertilizers would result in superior growth or visual quality. Gilman et al. (2000) found no response to applied phosphorus (P) or potassium (K) in live oak, but this species rarely exhibits deficiencies of any nutrient element in the landscape.
Because responses to fertilization appear to vary greatly among species and in different soils and environments, it is important to study the growth responses of individual species, especially on nutrient-poor soils. The purpose of this study was to determine how four trees commonly grown in south Florida respond to two commercially available types of fertilizer, a typical turf fertilizer that contains no Mg or water-soluble micronutrients and a palm fertilizer that contains large amounts of K, Mg, and soluble micronutrients, and to determine if fertilizer rate is important, both during and after establishment.
BarkerA.V.PilbeamD.J.2007Handbook of plant nutrition. CRC Press Boca Raton FL
BroschatT.K.MooreK.A.2010Effects of fertilization on the growth and quality of container-grown areca palm and chinese hibiscus during establishment in the landscapeHortTechnology20389394
DickeyR.D.1977Nutritional deficiencies of woody ornamental plants used in Florida landscapes. Univ. Florida Agr. Exspt. Sta. Bul. 791
GilmanE.F.YeagerT.H.1990Fertilizer type and nitrogen rate affects field-grown laurel oak and japanese ligustrumProc. Florida State Hort. Soc.103370372
KuoS.1996Phosphorus p. 869–920. In: J.M. Bartels (ed.). Methods of soil analysis. Part 3. Chemical methods. Soil Sci. Soc. Amer. Madison WI
MillsH.A.JonesJ.B.Jr1996Plant analysis handbook II. MicroMacro Publ. Athens GA
ScagelC.F.BiG.FuchigamiL.H.ReganR.P.2008Rate of nitrogen application during the growing season and spraying plants with urea in the autumn alters uptake of other nutrients by deciduous and evergreen container-grown Rhododendron cultivarsHortScience4315691579