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Updated: Nov 23, 2023

Welcome to Hejgro’s Guide to Sustainable Foraging! Suitable for beginners and foragers with some experience, this 9-point deep-dive covers the knowledge required to stay safe and to support nature in sustaining itself, whilst we choose to harvest some of its fruits.

  1. Start with what you're comfortable with

Foraging varies wildly by geography, season, and native/non-native plants. Start by researching a few easy-to-identify edible plants in your region. Wild greens, such as nettles, wild garlic and dandelion leaf, are a good place to begin. Join a local foraging walk to get an overview from an experienced forager, and start to learn the skills required to identify edible plants. Hejgro’s own foraging walks are an ideal place to get underway!

Identifying a plant in the wild for the first time can be exciting, but if you are foraging for foods you have never eaten before, it is best to treat your body the same way you would treat a newborn: try a few mouthfuls, then wait a day to see how you feel.

2. Never eat something if you are not 100% sure what it is

The UK plays host to plants which cause minor and severe topical or internal irritation, and plants which are deadly when ingested by humans. Never, ever eat something if you are not 100% sure what it is. Always use more than one method of identification - yours and others’ knowledge, your sense of smell (we intuitively know not to eat something that smells unpleasant), a plant ID app or book. Of particular importance here is learning which plants look similar to each other, where one is edible and the other poisonous. In May, I wrote a Hejgro blogpost on this very topic - do check it out.

Part of foraging sustainably requires safe practices to ensure longevity of plants (and people!). Some basic knowledge goes a long way towards clearing up misconceptions. We are often afraid of mushrooms, for example, perhaps because there are so many varieties that closely mimic edible ones. Mushrooms need to be ingested to have any negative effect - you could pick up the most toxic species and it won’t do anything unless it gets into your bloodstream.

3. Keep your impact and footprint as small as possible

Always leave behind some of each plant so it can continue its life cycle or be eaten by animals, birds and insects. Take no more than you plan to consume and only collect from plentiful populations. Not every foraging trip needs to result in a big yield - enjoying time outdoors and improving your awareness of what grows around you can be enough.

Forage in small groups and avoid creating new paths. Be careful not to trample plants and other flora as you search for edible treasure. Don't be tempted to reveal good foraging spots on the internet - this could result in overcrowding and degradation.

4. Know your annuals, biennials and perennials

Knowing if a plant is an annual, biennial or perennial enables you to harvest plants sustainably to ensure they can continue to propagate.

Annuals go through their life cycle in one year. They germinate, grow, bear fruits and flowers, and die off in the same year. Picked in early spring to early summer, Cleavers’ (aka Sticky Willy) young, bright green leaves can be stewed overnight in a refrigerated pint of water for a lymphatic cleanse in your adrenal glands. Part of the same plant family as coffee, roasted brown (not green) Cleavers’ seeds make a tasty coffee drink in autumn and winter.

Biennials develop roots, stems and leaves in year one. Flowers and fruits arrive in year two. Harvesting some, but obviously not all, leaves and roots can be done in year one. Wild Garlic Mustard (also known as ‘Jack by the hedge’) has kidney-shaped toothed leaves in its first year. The leaves become more heart-shaped in year two and the plant throws up a flower stalk with a cluster of white four-petalled flowers at the top. The leaves and flowers can be lightly steamed or used raw in salads. After flowering, the seeds can be used as a mustard-flavoured spice or seasoning, or used to make a rustic wholegrain mustard.

Perennials regrow every spring and live longer than two years. They continue to bear flowers and fruits for several seasons after initial growth and grow stronger each year. ‘Perennial’ loosely refers to all non-woody plants which are not trees, shrubs or bulbs. They can be deciduous (leaf-shedding) or evergreen. Herbaceous perennials describe the sub-group of perennials which die back in the winter, such as Dandelion. Elder is a deciduous, herbaceous, perennial, woody shrub (just to confuse things) with edible flowers and berries. Early September is the perfect time to harvest berries, when all of them are deep purple/black. They must be cooked before consuming, so if you would like someone else to do the prep work for you, give Hejgro’s Pontack Sauce with elderberries a try - lots of serving suggestions and health benefits can be found at this link.

Long thin leaves of Cleavers (aka Sticky Willy), large leaves of Wild Garlic Mustard (aka Jack by the Hedge) and a ripe, drooping umbel of the Elderberry. Photo credit for all: Claire Jefferies

5. Know the best way to harvest each plant

Knowing which part of the plant to harvest when will give you wild food at its most flavourful and nutritionally beneficial, and will also sustain a plant’s good health. The most potent part of a plant is wherever the energy is currently stored. In spring that is usually the leaves - sap is also rising through trees at this time, bringing nutrition from the soil. Once the plant is nourished, it propagates by sending out flowers (usually in summer), before going to seed (usually in autumn/winter). Once that happens, some plants die, but the species continues as seedlings the next year (annuals/biennials). Others draw the energy down to their roots for winter (perennials). Some plants’ leaves die in winter, though not all. Energy stays in the root until spring and also in the seed until it germinates again.

Every plant has a preferred way to be harvested sustainably. The method you use will be influenced by whether the plant is annual or perennial, herbaceous or woody. Herbaceous plants produce soft flexible green stems and woody plants produce a hard woody stem. Other factors include which plant part you are after, the site, time of year and climate conditions.

Begin by ensuring all parts of a plant look healthy and are a typical colour for the species - soil contaminants or nutrient burn (a sign of stress when plants are given excessive nutrients) can change this.


Never strip a plant of all its leaves - this can weaken the plant through stress or enable pests and diseases to gain a foothold. The plant may also seed prematurely which can weaken the gene pool of that species. Younger spring leaves are best for fresh salads (e.g. Chickweed), before they toughen up. Certain edible leaves are much more bitter when raw (e.g. Dandelion) and cooking them helps to leach out the bitterness. New leaves of certain herbaceous plants appear as ‘spears’. These leaf stalks/leaf shoots can be treated like plants we cook regularly in the kitchen e.g. celery or asparagus. Foraged examples include Common Hogweed or Japanese Knotweed - more on invasive species can be found in point 7 below.


Harvest flower buds when they are young and firm to the squeeze (e.g. Oxeye Daisy, Wild Garlic or Dandelion). If flowers in bloom are clustered on a multi-branching stem, like Yarrow, or on multi-branching forked stalks, like Elderflower, then cut the whole stem or stalk and batter fry/pickle them as a cluster.

When looking to harvest essential oil-laden, aromatic flowers (e.g. Lemon Balm), these are best harvested just before they fully open on dry mornings. This ensures their maximum potency and medicinal value. The best results for aromatic plants are achieved from a harvest following successive warm dry days.


It can be tricky to correctly time the harvest of herbaceous pre-flowering stems. Cow Parsley can be soft, tender and tasty when young. You need to peel the thin fibrous outer skin off before eating. Plants soon develop strength and rigidity as they grow, and with it, fibrousness. Within a few days a plant part can go from tasty to inedible.

Be conscious of picking from stems without damaging the plant and be clean with your cutting by using a sharp knife or secateurs. Make cuts just above a node - the bud location on a stem. This will allow dormant buds to flower in the future. It will also protect the plant by reducing the chance of a dead stem rotting and infecting it.


Fleshy fruits should be harvested when almost ripe. Elderberries can be cut by the whole stem then stripped at home to leave minimal stalk. Certain products made from wild fruits, like jams and sauces, work much better with the higher pectin content of slightly under-ripe fruit. Hawthorn berries are reasonably high in pectin and make a lovely jam or jelly. They come away easily with a small twist between thumb and fingers. Don’t yank it or you will likely pull off the new growth spurs of next year’s flower buds. Before harvesting from August to November, do a quick test to see whether they are ripe - you don’t want to see green inside. Check out Hejgro’s own delicious Apple and Hawthorn Jelly at the link below, complete with serving suggestions:


Seeds can be harvested by placing a paper or carrier bag over the ripe seed-heads. The heads can be shaken immediately or left for a few days in good weather to drop naturally. Common Hogweed seeds are ready in early autumn and, once toasted and ground, taste of cardamom and citrus. Here is a tried and tested recipe for Hogweed Seed Parkin Cake


Barks are typically harvested in spring when the sap rises from roots to leaf buds as this is when the bark will peel away easily. At this point, the plant generally has higher concentrations of other medicinal components as well. Never peel bark away in complete circles around branches - above this point the tree will die. Only remove bark from branches and not from the main trunk. Willow bark has been used for millennia to treat pain, inflammation and fever as it contains salicin - similar to aspirin but without any irritation to the stomach lining.


Spring-harvested roots will likely have experienced winter frosts that convert complex carbohydrate stores into simple sugars, so can have better flavour. Autumn is good for harvesting biennial or perennial roots as this is when the plant draws down sugars and other nutrients, before returning to dormancy. The roots of biennial plants are best harvested at the end of their first year. Burdock has a large, fleshy taproot, best harvested in autumn of its first year or spring of its second. Roasted for 15 minutes with salt, pepper and olive oil, it tastes wonderful with sesame seeds and soy sauce added before serving.

For harvesting a whole plant, gather it just before flowering, cut the plant at ground level, or carefully uproot it using a fork, gently shaking the roots.

6. Practise encourages sustainable foraging

We know that repetition of any mindful activity increases presence and awareness. When you see a plant and know its name it is no longer ‘just a weed’. You begin to build a sense of connection with it and this changes its value in your mind. As you practise foraging, your gaze widens from the path in front of you to everything around you. This wide-angle lens allows you to take in an area of light green in one place, the purplish green of nettles in another, or the river ahead. When you are no longer the main character in a green space, but part of the landscape, the experience becomes more meditative and present. Once we see what exists around us, we can begin to see how our food system is interconnected with natural ecosystems.

Particularly in the Western world, we tend to think about food in terms of money and pleasure. Foraging can become a way to see things through a different lens, to think about the natural environment, living more sustainably and the work involved in both food gathering and food production. It can help us let go of the consumer mindset of someone raised in a capitalist food system, which tells us to take as much as we can and is predicated on huge amounts of waste.

7. Forage for invasive species

Most of us will have imbibed a learned hatred of certain plants - nettles because they sting you, red berries because ‘they are poisonous’ or invasive plants because ‘they are dangerous’, although we are not clear on the details of why or how. Fallopia japonica, or Japanese knotweed, is at the top of the list of invasive plant species in the UK because of its reputation for destroying house foundations. It may be surprising to learn then that Japanese knotweed is both safe to touch and eat, and the young shoots are reminiscent of lemon-rhubarb in flavour. They work well in purees, jams, sauces, fruit compotes, soups, wines, ice cream and even gin. You can also eat the seeds from the pods, which look and taste a little like miniature fresh green peas.

Japanese knotweed contains high amounts of Resveratrol, a naturally occurring powerful compound that acts like an antioxidant. It is most commonly found in the skin of grapes and red wine. A diet high in antioxidant-rich foods promotes high levels of HDL (good cholesterol), low levels of LDL (bad cholesterol) and suppresses inflammation.

Japanese knotweed: Early growth, in flower and in full bloom. Photo credit for all:

Many invasive plants are healthy and delicious, and have huge medicinal and nutritional benefits. Harvesting them frees up habitat for native plants to flourish. We are not just going to eradicate invasive species - learning to live with them, eating them and even considering if they could be helpful to us seems to be a far more sustainable approach.

8. Know Your Urban Soil

Knowing historical uses for a piece of land is helpful to avoid contaminated soil. Commonly-found contaminants include arsenic, cadmium, lead, mercury and zinc. Their presence is usually related to previous industrial activity, heavy traffic, use of agricultural pesticides, or other chemical applications such as lead-based paint on a building. Long-term residents or local library and council records can provide information on an area’s previous land use. A more seasoned forager may pay for some soil testing on a piece of public land but, as a rule, it is best to forage in areas out of town, and away from major roads, landfill sites, old building foundations, power plants, railways or canals. Also remember, dogs go to the toilet by a path or road, so head away from the main drag to find unspoilt growth.

9. Permission to Pick

In the UK, you need to ask permission from the landowner to forage on private land, or you may need to apply for a permit. It is illegal to dig up or remove a plant without permission from the landowner or occupier (this includes algae, lichens and fungi). Some species are specially protected against picking, uprooting, damage and sale. A list of these can be found here: Schedule 8 of the Wildlife and Countryside Act (1981).

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