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.

Work opportunities

Climate and weather

Taxonomy and origins:
Centers of diversity

Structure, function, & processes:
CMGH Chapter 2 supplement
Flower parts:
Hormones and alkaloids
Roots stem leaves flowers seeds
Abscisic acid, pollination, fertilization
Parts 53
Seeds, stilt roots 10

Soil and compost
Composition and function
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:

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

Vectors viruses & bacteria
Fungus basics


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

Pesticides: Nerves & acetylcholine, poisons & horticulture

Integrated Pest Management

Indoor plants

Lawns and turf

Woody plants

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


Poisons and medicines::

Golden Gate Park field trip

OH53 Landscape Horticulture
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.

Fall semester:

Work opportunities 95

Safety and pesticides
Safety, insects & fungi

Pruning trees and woody plants
Tree pruning and planting 46

Herbaceous perennials

Drainage, erosion control, and mulches

Field propagation

Compost and recycling in the garden

Humans and small engines
Part I:
Part II:

Part I:
Part II:

Fixing irrigation
Part I:
Part II:

Erosion & drainage

Building rock walls

Crew supervision and delegation ???

Spring semester:

Working as a gardener 51

Body mechanics and injuries

Gardening approaches 124

Drip irrigation

Maintenance schedule


Crew discipline ???

OH55 Tree Care:
Tree basic vocabulary 40

Tree selection 45

People are walking trees 16

Tree death and disease 48

Tree mortality 47

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


Poinsettia crop
crop update
another update

Potting soil ingredients


Conservatory of Flowers tour

Park Nursery tour

Heating and cooling systems

Humidity & poinsettias update

EC Meter and the Dosatron


Society and plant use

Life cycle and genetics

Growing environment




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:

OH 70A Beginning design:

Site inventory and basic drafting
Site survey
Site survey 39

Garden styles
Miscellaneous styles 47

Hardscape materials

Section elevation

Plant selection and placement

San Bruno Mountain field trip

Drawing plants

Basic principles

Gondwanaland designs

SFBG field trip

Isometric drawing

One point perspective drawing

Garden structures ???

Hand drawn plans

OH70B Advanced design:

Sustainability and green building ???

Lighting ???

Water features

Chinese gardens 23

Plant ecology and community


Maintenance and design

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.






Grasses 59

Conifers 58

Tree identification and classification 42

Miscellaneous garden posts

School gardens

Story cards

Basic curriculum

Botanical gardens

Glen Canyon, San Francisco