Sampling Procedure for Foliar Analysis of Forcing Azalea1

Abstract

Forcing azalea (Rhododendron sp. cvs. Redwing, Mission Bells and Gloria were subjected to sufficient and low levels of N, K, and Ca, and the difference in concentration of these nutrients was measured and termed “differential”. Immature, recently mature, and old leaves were sampled periodically from current shoots during development. Ca differential was not related to sample position. N differential was exhibited in a similar manner but was best expressed in older leaf tissue during late growth. The magnitude of the K differential was related to both sample position and sample date; the largest expression occurred in young leaf tissue during early growth and on older leaf tissue during late shoot development. The best single sample position for foliar analysis of these nutrients was the most recently mature leaves on current shoots.