Grapefruit, ready for picking

Q & A: ASK THE EXPERTS

Q - My mature orange and grapefruit trees have wonderful fruit and bright-green full-sized leaves. Why are both trees currently dropping loads of leaves?

A - Natural leaf drop on citrus is not uncommon this time of year. However, it also may be caused by environmental conditions or gardening practices, remarks Olin Miller, University of Arizona Maricopa County Cooperative Extension (MCCE) Master Gardener. A typical cultural cause of leaf drop is too much water, especially in winter when there isn’t
much growth occurring.

Another common environmental cause is large temperature fluctuations, such as when daytime highs in the 80s plunge to nighttime lows in the 30s. Mature citrus should be watered deeply at 21- to 30-day intervals in winter. Table 2 of University of Arizona Cooperative Extension’s publication Irrigating Citrus Trees provides watering schedules at: cals.arizona.edu/pubs/crops/az1151.pdf.