A Guide to harvesting wild plants for food and medicine.
How to harvest wild plants
Firstly it’s important to say that when harvesting wild plants, you should make sure that all leaves, flowers, roots, and seeds are always of the usual colour for that given species.
Do not use any blackened, mouldy, miscoloured or otherwise damaged material. Handle plants carefully to avoid bruising and spoiling delicate leaves.
The cutting of stems should ideally be done with sharp secateurs or a knife,just above a node, which allows the dormant buds below to spring forth, and offers little chance of the dead stem rotting and infecting the plant. When using whole plants, harvest just before flowering, cutting the plant at ground level. On perennial plants, take just some of the growth, thereby allowing the plant to flower.
Flowers Aromatic flowers are best harvested just before fully opening, on dry mornings, to ensure their maximum potency.. Some species can be harvested continuously over a number of days or weeks.
If the flowers are clustered on a multi-branching stem, like yarrow (Achillea millefolium) or elder, then cut the whole stem and snip off the flowers later. Always remove as much stem as possible from the flowers before use.
Seeds can be harvested simply by placing a paper bag over the ripe seed-head. The head can be shaken immediately or left for a few days in good weather to drop naturally. Or, cut the stem and hang the plant upside down and leave for a few days.
Fruits should be harvested when almost ripe. For plants such as rowans and elderberries, cut the whole stem, then strip at home leaving minimal stalk. Sea buckthorn and other juicy berries can be harvested on the stem, which after cutting should be frozen and then the berries can be gathered. Dewberries sit on a little ‘cocktail stick’ stalk. Harvest this and discard after eating/using.
Barks are typically harvested in spring when the sap rises, because at this time it will peel away especially easily. However, evergreen and conifer barks can be harvested all year round, and some people may also harvest barks in autumn, Once again the bark is pretty easy to remove. Branches from specimens 3- 5 years old are suitable for many medicinal barks such as cramp bark (Viburnum opulus) and oak (Quercus spp).
The age of woody branches can be deduced by tracing back the number of the visible scars on the branches known as the abscission points. These appear as closely bound ripples on the stem and are produced where previously buds formed and burst on the preceding year’s growth.
Generally, the inner bark will be required for medicine. Essentially, this is where the plants vascular system is found, and consists of the actively dividing cambium layer of cells and its two distinct networks; the xylem and the phloem.
The xylem cells connect the roots to the rest of the plant, whilst the phloem connects the leaves to the rest of the plant. In any woody plant species, the cambium layer of cells in the stem, branch, or trunk, always continue to generate new cells, steadily increasing the plants girth.
The newest xylem cells are situated on one side of the cambium, towards the centre of the trunk or branch, whilst the phloem cells are situated just the other side, nearest to the bark, consisting of soft, corky tissue.
When barks you want to be taking the softer phloem, cambium layer, and new xylem cells, as this will contain the widest array of constituents. Inner barks should easily peel away when harvested in spring. Never peel bark away in complete circles around branches, for above this point the tree will die. Never remove bark from the main trunk.
Roots are mentioned in most herbal medicine books as being available to harvest either in the autumn or spring. I tend to favour the autumn for harvesting perennial roots, as this is when the plant returns to dormancy and has higher concentrations of nutrients and other medicinal components.
Early in the spring, (if and when you can find it!) the plant is already using up its storage reserves as it re-emerges from winter slumber. For busy people with hectic lives, much of our choice will be pre-determined by time allowances. “So, harvest whenever you can” – is still the advice I would give to busy people, making them aware of potential shortcomings from possibly reduced concentrations of certain constituents.
The roots of biennial plants are best harvested at the end of their first year. Tap-rooted plants will need substantial digging and coercion to remove the root intact. For fibrous rooted plants, mark out a broad circle around the plant base, then dig out a clod on the circle line, and shake loose the roots.
Leaves can be thought of as the most renewable of our plant resources. Many of the plants listed here can be returned to on a number of occasions throughout the year in order to gather fresh new leaves in a ‘cut-and-come again’ fashion, usually employed by gardeners.
The action of pinching out the growing tops of a plant, directly above a node, encourages it to rapidly produce more leaves from hitherto dormant lateral buds. Never strip any plant of all its leaves as this will either weaken the plant through stress, enabling pests and diseases to gain a foothold, or the plant may set seed prematurely, which only serves to weaken the genetic gene pool of that particular species. The golden rule is to take a few leaves from a number of plants at any given site.
Younger leaves are best, as they are far more succulent, and this especially applies to our tree leaves, such as beech, hawthorn, and lime trees. All these are good in salads at certain times of the spring. Some edible leaves are much more bitter raw, if they grow in full sun. Harvesting from plants which grow more in the shade alleviates this. Many leaves that are unpalatable raw are transformed when cooked.
New leaves of certain herbaceous plants appear as spears. These stem / leaf shoots are produced by larger plants such as hogweed (Heracleum sphondylium), sea-kale (Crambe maritima) and japanese knotweed (Fallopia japonica).
These spears are very succulent and tasty, and some of the best wild plant food to be had. Pre-flowering stems are similarly succulent when harvested correctly.
I think it is trickier to correctly time the harvest of pre-flowering stems than it is to harvest new leaf shoots, and only experience of the species in question, alongside knowledge about the idiosyncrasies of a particular micro-climate can help you get accustomed to when is the best time to harvest.
Take cow parsley (Anthriscus sylvestris) or alexanders (Smyrnium olusatrum) pre-flowering stems as examples. When bang-on; being soft and young, they are lovely, after peeling the outer skin off. However, they soon develop rigidity, and with it, fibrousness, thereby becoming inedible.
Foragers would do well to examine the life of the esteemed herbalist Nicholas Culpeper (1616-1654). He was a botanist, astrologer, apothecary-physician of the poor, and a prolific writer on medicine during his short life. He was by default a forager of some skill and expertise to have known as many plants as he did.
For example, his ‘Physical Directory’ (published 1648) discussed more than 300 species, of which the vast majority were easily found in Britain’s countryside. Over the course of a few years he noted (whilst treating thousands of poor people in the East end of London for free) the increased virtues of plant medicines when collected from the preferred habitats ‘they delight to grow in‘. If at all possible, his advice is still worth following when you go out harvesting plants.
Foragers also have a moral duty to ensure that plant resources are not diminished in their local areas, and given the fact that foragers get to know their know their area well, they are also in a position to actively conserve and promote plant life. We are always passively scattering seeds via our clothing and shoes, so why not actively do this?
Another idea could be to manage bramble invasions at woodland edges and such like. This will hopefully encourage the herbaceous understory whilst maintaining a fundamental action of brambles – they protect tree seedlings from animal herbivores. Many fruiting plants we hope to find when out foraging are natural woodland residents. All are greatly helped by bramble security guards.
Habitat management and creation therefore, are two of the easy ways that we can help sustain levels of productivity from our hedgerows and waysides when out foraging, or just simply out walking.
Thinning out overgrown areas to maintain diversity, let alone to increase it, can be argued as necessary in some of our under maintained woodlands, waste-ground and wayside habitats. In our woodlands, coppicing and pollarding are two ancient methods of management that increase productivity and diversity, and are still very much applicable today.