Identification and Harvesting
Copyright 2008 Alethea Kenney (email:
The information contained in this article is the sole property of the author and may not be reprinted without permission. Please use your own judgement when deciding to use herbs. Always consult with a qualified practitioner for diagnosis, prescription or treatment of any ailment you may have. I hope you enjoy the information!

Have a care when looking for different species of plants.   Some species are not common or found in sensitive areas and you may do much damage without realizing it.   In some areas, harvesting plants from the wild is illegal.   Public land use may require a permit.  It is YOUR responsibility to find out where and when or if a plant can be harvested or an area may be visited.   This information is for educational purposes only.   Please assume responsibility for your own actions.   Thank you.

Identification and Harvesting:
Scientific names, why do I care?  
  • Unique to each plant species, doesn’t change from place to place or internationally
  • Links plants together in families, genuses, species by similarities, primarily in flower structure
  • Get a good botany text or plant guide with explanations
  • Books have errors and the internet even more so.   Use websites that are maintained by extension services, universities or known to you as accurate.   
Family is the large group of loosely related plants.   This can be thought of as your own extended family.   Grasses are in the Poaceae family, mustard, broccoli, cabbage in the Brassicaceae family (used to be Cruciferae family for the flower petals in the shape of a cross)
Genus is a further subdivision of Family and is like a surname for the plant.   Alfalfa (Medicago sativa)  is in the Fabaceae family and Genus Medicago, which it shares with black medic (Medicago lupulina).
Species is the designation like a fingerprint for the plant, a plant shares the complete name of “Genus species” with no other plant.  But the Genus and species must go together.   Like asking if you know Jane?   Which Jane?  Jane Doe?   Doe is the Genus, Jane is the species.  Red Clover is Genus Trifolium and species pratense.   Genus and species are written in italics and Genus capitalized with species lower case.  Trifolium pratense, Fabaceae (Genus species, Family)
How leaves look and feel are clues, glaucous bloom (waxy coating) on stems differentiates raspberry canes from blackberry canes.   Blackberry canes are square while raspberry canes are round.  
Mint family plants have square stems (Lamiaceae) but not all plants with square stems are mints!!  
How to tell one plant from another:
  • Three field guides, at least one with photos makes it easier
  • Grow a nursery plot, label and learn plants from seed to flowering to winter
  • Don’t learn only flowers, some plants have inconspicuous flowers or aren’t harvested when in flower (ex.  burdock, raspberry)
  • Each plant has a genus and species, you need to know both or you don’t have enough info to identify
  • Learn plants by groups of characteristics.  Note the above ground parts and below ground (not always a root, can be a tuber or other type)
Above ground consists of shoot, leaves, flowers, seeds (in flowering plants, the exception is conifers)
Annual:  whole life cycle is in one growing season, seed to plant to flower to seed
examples:  calendula (Calendula officinalis)  
Biennial:  first year is a rosette (ring of sessile leaves), overwinter then second year shoot to flower to seed and death of plant
examples:  burdock (Arctium lappa), yellow dock (Rumex crispus), evening primrose (Oenothera biennis)
Perennial:  A plant that survives more than one season and returns each year to reproduce
examples: alfalfa (Medicago sativa), red clover (Trifolium arvense)
Woody plants: deciduous and evergreen trees and shrubs, can be difficult to determine where a plant falls in this category.   Poison ivy (Toxicodendron radicans) can be classed as perennial or shrub and some shrubs may be sapling trees.  Rule of thumb, if it has multiple stems it is a shrub, not a tree (but then basswood Tilia stump sprouts when cut and can be mistaken for a shrub).
Flowering plants consist of roots, stems, flowers and leaves.   Pay attention to all parts.
Stems have nodes and buds. 
Roots can be 
  • simple (dandelion Taraxacum officinale
  • creeping, a rhizome that is underground stem and gives rise to other plants
  • corm, tuber on the end
  • bulb (onion Allium species)
Leaf arrangement:
  • alternate
  • opposite
  • whorled (Galium species)
  • basal (dandelion)

Leaf type:
  • simple
  • compound: each “leaf” is referred to as a leaflet (walnut Juglans nigra)
  • complex compound: the leaflets are subdivided into leaflets
Plants are classified according to similarity of structures, particularly flower structure.   However, flowers are not the best way to identify plants in most cases since the flowers only appear for a short time each year or every few years.   Medicinals are not typically harvested at flower so learn to recognize the vegetative state.
Responsible Harvesting/Wildcrafting (Ref. 1):
  • Be aware of your environment, wet areas and bogs are damaged merely by walking on them   
  • Take leaves off trees and shrubs from outer edges of plants, bark from branches not core trunk and NEVER girdle a tree.
  • Harvest where there are many of that species and leave at least 80 to 90% of the community or stand.
  • Try to leave no trace, return soil carefully, replant disturbed plants.
  • Walk, don’t take motorized vehicles as they cause soil compaction, erosion, pollution.  
  • Do NOT harvest near roadways, wet areas drained off parking lots or other polluted areas, sprayed fields or ditches.
  • Plants can pick up heavy metals and incorporate them into their structure, becoming toxic even if you wash them.
  • Never harvest rare or endangered species, a list for your area is available from the NRCS office or DNR.
  • Get permission from landowners and ask about state and recreational areas, a permit may be required.  
When to Harvest
  • If you want to harvest leaves (ex.  mints) then usually do so before the plant flowers and in the morning just after the dew dries (there are exceptions).   The Native Americans divided medicinal uses of plants into pre and post bloom.
  • Flowers are best after they open completely in the morning after the dew dries.
  • Seeds when they are fully ripe or after they have dried on the plant.
  • Fruit must be completely ripe and not decayed.
  • Do NOT take any part that is discolored, bug eaten, wilted, damaged in any way.   This changes the chemical composition of the part, plants release chemicals in response to injury just like we do.  
  • Roots, if a  biennial, are harvested the first year fall or second year early spring before leaf growth, perennials in early spring or late fall when energy is in the root.  
  • Bark is harvested usually in the fall but spring after sap rises can work.  
  • These are guidelines and rules were meant to be broken.  If you need a particular herb but the time is not perfect (like white oak bark Quercus alba in midsummer) go ahead and harvest it.   But for storage and preservation try to follow the rules for best results.


Works Cited:
Green, James.  The Herbal Medicine Maker’s Handbook.  CA: Crossing Press, 2000.