Mimeo HO-81-5
Purdue University Cooperative Extension Service
Lafayette, Indiana
FERTILIZING WOODY PLANTS IN INDIANA
H. W. Gilbert and A. T. Leiser Horticulture Department
Applying fertilizer will not guarantee a healthy, vigorous growth of woody ornamentals. This desirable condition can only be achieved through the proper balance many environmental requirements-adequate water, good soil structure, good drainage, proper soil temperature, nutrition, etc.
The intent of this publication is to assist homeowners to properly select and use fertilizers. It has been prepared with the idea that the average gardener cannot afford the cost or the storage space to stock all types of fertilizers recommended.
The Indiana fertilizer law is designed to protect consumers from the exaggerated claims of certain fertilizer manufacturers who would add minor elements of doubtful benefit or "magic" ingredients which they claim will cure all gardening woes.

Plant Requirements*
Woody plants may be divided into two large groups on the basis of soil reaction (pH preferences. The pH is a measure of soil acidity ("sour") or alkalinity ("sweet’")- pH 7 is neutral; pH 8 is quite alkaline for a garden soil; pH 6 is slightly acid; pH moderately acid, and pH 4, very acid for a garden soil.
Table 1. Some Common Woody Plants Classified According to Soil Reaction Preference			
Group I (pH 6-8)	tolerant	Group II (pH 4.5-6.0) acid-loving	
Scientific Name	Common Name	Scientific Name	Common Name
Acer sp.	Naples	Cornus sp.	Dogwood
fiunymus sp.	Euonymus	Kalmia latifolia	Mountain Laurel
lorsythia sp.	Goldenbell	Ilex sp.	Hollies
fjaius sp.	Apples, Crabs	Leucothoe catesbaei	Drooping Leucothoe
fiatanus sp.	Sycamore	Magnolia sp.	Sweetbay-Magnolias
pyracantha sp.	Firethorn	Pieris japonica	Andromeda
Rosa sp.	Roses	Rhododendron sp.	Rhododendrons and Azaleas
Robinia sp.	Locust	Quercus sp. esp.	Oak
Salix sp.	Willow	Q. palustris	Pin Oak
syringa sp.	Lilac	Abies sp.	Fir
Viburnum sp.	Viburnums	Thuja sp.	Arborvitae
Haigela sp.	Weigela	Taxus sp.	Yew
Juniperus sp.	Juniper	Juniperus sp.	Juniper
*It appears that the average home gardener needs simplified fertilizer recommendations and that he usually is not able to obtain soil tests on which to base these recommendations. For this reason, the arbitrary group classification of Plant materials and resulting fertilizer program has been set up. These recommendations have been arrived at in an empirical fashion.