Wednesday, 31 October 2012

Yew (Taxus baccata)

Yew Berries in a churchyard in Oakham, Rutland.
Photo by Simon Garbutt (Wikimedia Commons)

Yew is an evergreen tree or shrub. Also known as Common Yew, English Yew and European Yew. It is native to Britain but can also be found in much of Europe, Asia and Africa. In Britain it is often found in and around sacred sites including graveyards and churchyards. Yews are often used as ornamental trees and hedges in domestic gardens.

Yews are long lived and considered one of the most ancient trees in Europe. The Fortingall Yew in Scotland is estimated to be around 5000 years old although it is difficult to gauge the exact age of these trees by counting the rings because a fungus often eats away at the tree leaving hollow rotten wood in the centre.


Yew has been used in folk medicine to induce menstruation, abortion and to treat diphtheria, tapeworm, tonsillitis, epilepsy and rheumatism. Native Americans used extracts for arthritis, fever and rheumatism. The wood itself is very hard and can be used to make furniture and tools. It can also be used for fuel and burns well as firewood.

Growing methods

Yew seeds have a low viability and are slow to germinate. They can be grown in pots but are probably best kept outside because they require exposure to the cold to germinate. Germination may take two winters or longer. A quicker option would be to take hardwood cuttings of the stem tips in late autumn. Cuttings should take around 3 months to root. Young plants should be kept moist but not over watered. Once established they can be trimmed or pruned hard without any undue damage.

Yew are slow growing but once established will provide around 30 cms of growth a year. They grow in most well drained soils but will also tolerate deep shade and drought. They make excellent hedges and are often used in topiary. Yew produces a dense evergreen canopy and a litter of needles thereby discouraging any plant growth underneath.

Raw edible parts

Nearly all parts of the Yew are highly poisonous containing toxic alkaloids including taxines or taxanes. It takes 50g - 100g of Yew needles to cause death in humans (Traditional Herbal Medicines: a guide to their safer use by Dr L. Karalliedde and Dr I. Gawarammana). Horses, cattle and other animals are also vunerable to poisoning. Poison will remain in clippings or prunings so care must be taken disposing of garden refuse containing Yew.

One part which is safe to eat is the soft red fleshy fruit, called an aril, which is found around the seed (see photo). These are available from female trees only. This red glutinous flesh is gorgeous, gooey, soft, sweet and highly recommended. To eat gently pop out the seed with thumb and finger and discard. The seed must not be chewed or swallowed under any circumstances. Yew fruits are available right now so keep an eye out for them. Shazzie, the Doxtor, shows how to eat them on this following YouTube video.

Wednesday, 3 October 2012

Opium Poppy (Papaver somniferum)

The Opium Poppy (Papaver somniferum) is an annual plant from the Papaveraceae family. It has been cultivated for a very long time for food, medicine, recreational drugs and as an ornamental plant. An archeological site in Northamptonshire (England) revealed eight opium poppy seeds dating from the early Neolithic period which is 5,800 to 5,600 years ago and suggests that this plant was farmed as a crop.

Opium Poppy (Papaver somniferum) flower

The opium poppy is an introduced annual and a garden escapee in the British Isles. It is usually grown as an ornamental and often found on waste ground. There are many other common names for this plant including common poppy, garden poppy, florists poppy and chessbolls. 

Papaver somniferum is generally regarded as being descended from P. setigerum which is a slightly smaller wild plant from the western Mediterranean. They are very similar and some regard both plants as being the same species.

Opium Poppy (Papaver somniferum) stems, leaves and capsules or pods

Growing methods

The opium poppy is an annual and it grows, flowers, fruits and seeds in the same year. The fruit is also the seed pod which ripens over a period of weeks and then opens little holes in the top where it releases many tiny seeds. Plants are short lived and are normally finished by the summer.

Seeds are fairly easy to obtain from plant catalogues but the seed sold for culinary use will also often germinate. There are many varieties and cultivars and they have different physical characteristics. Plants will readily self seed so if seeds haven't been collected, they will naturally disperse and come up again next year anyway.

To grow from seed, sow in the spring in situ about 30cms apart or just scatter for a more natural look. They can also be grown in pots and then planted out to their final position. Seeds can also be sown in late summer or autumn for overwintering. The Opium Poppy likes a sunny position and well drained soil. Flowers are produced from June to August and have fragile petals similar to tissue paper. They are usually pink, purple, white or red in colour and mature plants stand just under a metre in height. Seeds of P. somniferum tend to follow the shade of the flower. White seeds come from pale coloured flowers and dark seeds from dark coloured flowers. As the plants grow, the flower capsules or pods hang in a drooped manner and the pale green ruffled leaves hug the main stem.

The opium poppy is susceptable to insect infestations and fungal diseases such as downy mildew and powdery mildew. Plants are very sturdy and don't usually need staking but high winds and heavy rain can destroy the petals which are very delicate. To harvest the seeds wait for a few days of dry weather and for the seed head to dry out to a hard papery shell. The seeds will rattle inside if they are ready.

Raw edible parts

The seeds and young leaves are edible raw but read the Issues section below before imbibing.

Normally the black dried seeds are the parts eaten in the UK. They are popularly used to flavour sweet and savoury dishes such as breads, pastries and cakes. They can also be pressed to make an edible oil.

The leaves can also be eaten raw but before the flower pods have formed. They are crunchy and very similar to a lettuce leaf. There is no bitterness and when we can get 'em, we love 'em. However, be sure to eat them before the pods form.

An infusion can be made from the plant (usually the pods) but alkaloids present will be transferred to the tea. A search online will provide more information on the uses and dangers of this type of tea.


Much has been written about the opium poppy and its uses. Be aware it is a powerful plant containing addictive substances so should be used with a certain amount of caution. The potency of individual plants will vary with each species.

It has been reported that plants grown in cooler climates like that of the British Isles do not contain high levels of these substances. How much is high and are these levels dangerous? We have no idea and probably not providing the plants are used in a sensible manner. For example, eating the seeds is probably fine, making a daily infusion of Poppy Pod tea is probably not!

Photo: TeunSpaans (Wikimedia Commons), 2006.

Morphine is the principal alkaloid of the opium poppy and the raw material for producing heroin. Other alkaloids include codeine, thebaine, papaverine and noscapine. These substances can be found in the white latex of the plant. It is usually collected from the green immature pods of the plant by making incisions down the side. It can be seen oozing from the flesh of the plant - see photo. However, the whole mature plant (except the seed) contains this latex and so can also be processed to obtain these substances. The whole mature plant (minus the seed) after harvest is called poppy straw.

The seeds do not contain alkaloids. However, they can become contaminated as a result of insect damage to the capsule, or poor harvesting practices. Poppy seeds are, therefore, not always alkaloid-free. The European Food Safety Authority (EFSA Journal, 2011) states that: "Consumption of foods containing poppy seeds that are contaminated with opium alkaloids can lead to adverse health effects and to detectable contents of free morphine in blood as well as measurable concentrations in urine, sufficient to interfere with drug abuse testing." This might occur if single large portions of seeds or seeds that are raw and unground are consumed. The EFSA goes on to say that: "Food processing may decrease the alkaloid content by up to about 90 %. The most effective methods include washing, soaking and heat treatments, as well as grinding and combinations of these treatments."

That deals with the seed. Now on to the leaves. When is the best time to pick the leaves without subjecting oneself to a dreadful morphine addiction? One study (Morariu et Caulet, 2011) showed the level of morphine in the leaves of all genotypes began at the 43rd day after germination. The graphs in the study show no morphine in the leaves before this. As the pods formed morphine was detected in both roots and leaves. At this point the leaves contained the higher amount. Roots showed small amounts of morphine levels 23 days after germination.

This corresponds with general advice which is to pick young leaves and before the flower pods form. This is what we do. However, we have taken older leaves too (but only the odd one and not very often) and there were no obvious physical affects from this. This is probably because the plants we have are very low in alkaloids. However, to be on the safe side we do generally refrain from eating older leaves.

Is it illegal to grow this plant? It is not illegal to grow the opium poppy in the UK but it is illegal to process these plants into drugs. No surprise there then. It may, however, be illegal to grow them in other countries so always check first.