This is a blog by Thomas Wang, gardener and professor at City College of San Francisco.  Each post is a nature story with teaching diagrams.   The posts range the gamut of Thomas’ research interests from the qualities of soil and water to food and drug plants; from butterflies around San Francisco to the caterpillar within.

The goal is a stronger bond to the world that surrounds us, and an inner metamorphosis.  Good luck in your journey!

Note regarding City College of San Francisco Horticulture online class curriculum: In addition to, or sometimes in lieu of, the text book and reader assignments, students are asked to read selected entries here.  There are also a handful of youtube videos. Due dates will be assigned in class.  These entries are grouped according to the classes taught. 

Granted, there is some repetition from one class to another, and there is also material which builds upon the foundation of introductory classes.  As students, you are welcome to ‘jump ahead’ or read up on any topic, no matter what classes you are enrolled in.  The following sections are organized by Class, Topic, Numbered blog entry at, and Youtube link.

??? indicates entries on their way…still to be written

OH50 Introduction to Horticulture
This class is the first class any student ought to take in our department. It gives a good overall introduction to the science and art of plant work. Some of the more extensive notes in the Soil section were written for the OH 63 Soils class. The topics are listed in the order we follow based on the contents of the California Master Gardener Handbook.

Introduction: Work opportunities 95; Fuels 91

Climate & weather: Climate and weather 119; Climate 73

Taxonomy and origins: Centers of diversity 86

Structure, function, & processes: CMGH Chapter 2 supplement 139 & 140; Flower parts 147; Hormones and alkaloids 89; Roots stem leaves flowers seeds 88; Chemicals 74; Abscisic acid, pollination, fertilization 63; Parts 53; Seeds, stilt roots 10

Soil and compost: Types 126; Composition and function 77; Cation exchange capacity & colloids 62; Food webs and organic matter 61; Basics and chemistry 60; Profiles etc 41;
Serpentine soils etc 8

Fertilizer and amendments: Nitrogen 93

Water & irrigation: Soil water and tree relations 43; Irrigation notes 22

Pathology: Plant pathology 151; Vectors viruses & bacteria 87; Fungus basics 64; Tree death and disease 48; Tree mortality 47

Propagation: Cuttings 80

Entomology and invertebrates: Bee love 32; Larvae 31; Invertebrates rule 29; Insect pests 9

Weeds 105; Nerves & acetylcholine, poisons 103

Integrated Pest Management 106

Indoor plants

Lawns and turf

Woody plants

Vegetables and fruits: Challenges 20; Day length etc 13;


Poisons and medicines:: Coca and cola 50; Healing with plants 25; Betel nuts & dosage 11;

Golden Gate Park field trip

OH53 Landscape Horticulture & OH 55 Tree care
The notes here are from two classes I have been teaching with Gus Broucaret for the past dozen years. Landscape horticulture class concerns basic maintenance in the garden. Its focus is primarily hands on and practical – to help and guide gardeners and landscapers in their day to day work. The class is significant in our emphasis on safety and small machines. The notes for the tree care class, which is offered every two or three years or so in the Spring semester, is also included here.

Fall semester:

Work opportunities 95

Pruning 137

Safety and pesticides 142; Miscellaneous 110; Safety, insects & fungi 111

Seeing the world as a tree 145; Tree pruning and planting 46; Tree selection 45; Tree basic vocabulary 40; People are walking trees 16

Herbaceous perennials 150

Drainage, erosion control, and mulches 152

Compost and recycling in the garden 131

Humans and small engines 130

Crew supervision and delegation ???

Erosion & drainage

Building rock walls 128

Spring semester:

Working as a gardener 51

Body mechanics and injuries 66

Gardening approaches 124

Drip irrigation

Maintenance schedule


Crew discipline ???

OH58 Greenhouse production & OH65 Propagation
While there are a few notes here, these are not classes that I usually teach. They are generally taught by professor Malcolm Hillan. Happen to have some help this time around, and all the credit here lies with professor Tom Perlite. The growing of plants, and the general principles related to their care, is relevant to all the classes.

Greenhouse history 134;

Location 141

Poinsettia crop
crop update

About potting soil ingredients 149

Coverings 146;

Conservatory of Flowers tour

Heating and cooling systems

Propagation 120, 121, 122, 123

Cannabis 118

Cuttings 80

Mimic natural habitats



OH70 Landscape design
If you want to design gardens or landscapes, this is a good series (two classes) to take. Some people who have design experience from interior or industrial or art related realms jump right in. Others wait till the end to take the design classes – learning plant Identification, construction, characteristics of soil and water – before committing. Either way, you will learn how to draw a good set of plans. Afterwards, students tackle either residential yards and public spaces, or go on to graduate school if they want to become a landscape architect. We focus on the importance of knowing your plants and their ecology in relation to the overall design. We teach you to see the garden as a dynamic multi dimensional creature that requires care and maintenance over time. Heres the reading list according to our curricula itinerary:

Beginning design:

Site inventory and basic drafting 143; Site survey 136; Site survey 39

Garden styles 129; Miscellaneous styles 47

Hardcape over time 148; Hardscape & design 132; Hardscapes 112; Hardscape materials 71

Section elevation 133

What plant where? 138; Plant placement 81

Drawing plants 94; Hatching 75

Basic principles 135

Gondwanaland designs at another blog site:

Garden structures ???

San Bruno Mountain field trip OH70A 113

Hand drawn plans 144

Advanced design:

Sustainability and green building ???

Lighting ???

Water features 79

Chinese gardens 23

Plant ecology and community


Maintenance and design 109

OH76 Plant Identification
These notes have little to do with the actual plant identification classes offered at CCSF. Nevertheless, this seemed like the best heading to place the following entries. Observing plants and learning their names and habits will make the world come alive for you, and sharpen your senses and mind.

Chaparral 127

Bromeliads 92

Camellias 90

Cactus 85

Piperaceae 82

Grasses 59

Conifers 58

Tree identification and classification 42