Summer vacations are over, the kids are going back to school and the weather is a little milder. Many folks have the time again to do some late summer gardening. Not only is it time to do maintenance, but you can take advantage of the end of the season sales at the plant nurseries.

The most important issue concerning planting in late summer and fall is watering. You can imagine that since the plant has less time to establish a root system before winter, it will be more important to check the soil and water as needed through the winter. Because our winters can be predictably dry, watering one to four times a month is often necessary. When planting perennials, be sure to remove flower spikes, so that the roots have a chance to establish.

Autumn is when we can deal with certain disease problems. It may be useful to dispose of fallen leaves that are infected with fungal spores such as powdery mildew, leaf spot or rust to reduce the infection potential for next year. To play it safe, don’t place the diseased material in the compost.

Managing insect populations if often beneficial in the fall. Controlling many insects such as spider mite, woolly aphid, elm leaf beetle and borers may significantly reduce the insect’s breeding population to prevent damage next year.

A more controversial issue is about fertilizing in the fall. We know from university trials that fertilization of the turf grass is of significant benefit when done in the fall. Feeding woody plants such as trees and shrubs is generally not encouraged except for the application of micro-nutrients such as sulfur, magnesium and iron.

Against contemporary theory, my experience has shown that feeding herbaceous perennials (those that die back to the ground at frost) in early September is when these plants are starved from flowering and seed set, and are “regrouping” for the next year.

Generally, we have plenty of phosphorous and potassium in our soils, but we are lacking in the all-important nitrogen. I prefer to fall feed with a low nitrogen analysis of 8 to 14 percent such as that found in products containing alfalfa meal (Alpha One). This material is also rich in many micro-nutrients that your perennials need.