Need Help?

Allan designs and plants flowering gardens in Montreal, Zone 5 [USDA Zone 4] .

See website, design work and favorite flowering plants at

Consultation and coaching for do-it-yourselfers is provided. Occasional emailed questions are welcome and answered free of charge. Oui, je parle francais.

See my work on Pinterest at Garden Guru Montreal

Entries in Jeff Gillman (1)


How to Deal with Contradictory or Mythical Garden Advice; a book review for


Decoding Gardening Advice; the science behind the 100 most common recommendations, Jeff Gillman & Meleah Maynard, Timber Press

The benefit of this book to gardeners is that it takes advice out of the realm of folklore, and places it under the spotlight of horticultural and botanical science.

The authors maintain that the most serious drawback to successful and effective gardening is that people are ill informed. They believe that a lot of gardening advice is confusing, dubious, or bad.  Some well meaning gardeners unknowingly twist the facts, others are ignorant of them, and still others innocently hold on to stale-dated knowledge that no longer stands up to contemporary scientific scrutiny.

Is it possible that unsuspecting gardeners, confused when they are bombarded with contradictory advice, consider gardening a joyless activity? The authors believe so; and that has been their impetus to write this book.

Eight major gardening subjects are covered in an examination of the one hundred most commonly received  garden recommendations. The topics are related to soil, water, pest, disease, and weed control, mulch, annuals, perennials and bulbs, trees and shrubs, vegetables and fruit, and lawn care.

In order to evaluate the usefulness and worthiness of the most often-received guidance, the authors classify conventional gardening information into three categories: - advice that is good, advice that is debatable and advice that is just wrong. The reader will be amazed to learn how much erroneous information has been perpetuated as garden gospel, the amount of information that cannnot be substantiated as either true or false, and how much folklore is considered wise garden advice.

In the chapter on soil, an example of good advice is - Create an environment that is favorable to earth-worms. Earthworms are nature’s tilling machines. They do a great job of making nutrients, air, and water available to plants.

In that same chapter, debatable advice is to fertilize perennials and shrubs every year. We do not see a reason to fertilize perennials more than once every few years if the soil is good, meaning you add compost or other organic material on a regular basis.

Closing the chapter on soil is advice that is considered just wrong: add sand to clay to improve drainage. …when sand and clay are mixed together they blend in such a way that they create a dense, heavy mess – one with a consistency akin to wet concrete.

Advice that is good is confirmed with scholarship and research. Advice that is debatable, because science and experience can neither confirm nor refute it, is treated as a grey area for which there is no right or wrong answer. In such situations, choosing one way or another is a matter of personal preference. Advice is deemed bad when it is contradicted by science, or research, or fact-based experience.

For each one hundred recommendations, the authors explain every practice, the consequences of following the advice under scrutiny, how they believe the garden task ought to be executed, and a summary opinion or recommendation.

There is a new generation of gardeners, who do not wish to toil in their back yards; nor do they  wish to spend a lifetime exploring and testing conventional advice in order to determine the correct way to do anything. These contemporary hobbyists find no pleasure in discovery. They are the antithesis of the traditional gardener who finds joy in trial and error. Members of this non-traditional generation want to do it only once; and they need get it right the first time.

This manual, therefore, will provide accurate information to help them make wise gardening decisions. As well, it will be clarifying to those who have been bamboozled with botanical folklore that is closer to fiction than the truth. The authors were prescient in choosing to write this book.  We should be grateful.

Jeff Gillman, associate professor of Horticultural Science at the University of Minnesota, lectures and conducts research on woody ornamental plants and the abuse of pesticides. His scholarly public-ations cover a broad range of topics, including spider mite control, soil amendments, and treating plant diseases using organic means.

Meleah Maynard, master gardener, journalist, editor, speaker, and garden columnist, writes regularly for regional and national magazines.