Sweet Grass

Hierochloe odorata / Anthoxanthum nitens

Herbs gallery - Sweet Grass

Common names

  • Holy Grass
  • Manna Grass
  • Mary's Grass
  • Seneca Grass
  • Sweet Grass
  • Vanilla Grass

Sweet grass (botanical name Hierochloe odorata) is an extremely enduring plant that grows perennially. As the stems of the leaves of this plant are not firm and, hence, they grow up to a length of roughly 20 cm (7.9 inches) and subsequently they grow externally horizontally to about 100 cm (39 inches) by the end of summer. The leaf base, just underneath the surface of the soil, is wide and white hued, without any bristles or hairs. On their underside, the leaves are glossy and also do not have any hairs.

While growing in the wild, the leaf bases of sweet grass, also known as holy grass or manna grass, are often purple-red hued, indicating that the soil is deficient in phosphorus content. More than a few strains of sweet grass exist - there is a standard strain which is harvested once or two times every year. In addition, a polyploidy strain, which occurs naturally, grows more rapidly and this variety can be harvested thrice to five times a year.

Sweet grass has the aptitude to spread very fast by means of its creeping rhizomes and has the ability to withstand extreme cold conditions. The plants growing in the region of the Great Lake start blooming during spring.

Sweet grass has a number of uses. It is very effective for restoring and mitigating wetland and riparian as well as spring protection restoration. This species also possesses the potential for soil conservation by controlling erosion.

Parts used



Sweet grass is also known as the holy grass because on the All Saints' Day, people in northern Europe strew it in front of the church doors. This was probably done because when one walked over the strewn fresh grass, it brought out a pleasing aroma. In France, people used sweet grass to add essence to candy, soft drinks, tobacco and perfumes. People in Europe frequently substitute this species or use it interchangeably with Hierochloe alpine. In Russia, people used Hierochloe alpine to make their teas more flavourful. Even to this day, people use sweet grass in flavoured vodka, for instance the Polish Żubrówka.

The leaves of this species are collected during the summer and dried up naturally in sunlight or by employing artificial processes. The dehydrated leaves of sweet grass are subsequently woven into braids that are either used in the form of incense or burned. When burnt, the dry leaves give out a pleasant aroma akin to that of vanilla and it forms a vital part in several sacred ceremonies among the natives of North America as well as a number of aboriginal people in Europe. The dried up sweet grass leaves are also used for therapeutic purposes, especially in herbal teas. The plant also yields an essential oil that is used for seasoning foods as well as alcoholic beverages.

Sweet grass encloses a compound called coumarin, which is responsible for the plant's distinct aroma. Coumarin possesses anti-coagulant or blood-thinning attributes. Findings of a number of scientific studies have revealed that coumarin as well as related chemicals may be useful in lowering high-protein edemas, particularly lymphedema. The downside is that coumarins are also known to be toxic and may prove to be carcinogenic (cancer causing) when taken in excessive dosages.

The indigenous people of North America have been specially using sweet grass traditionally for their religious ceremonies as well as for specific therapeutic purposes. These tribal people inhale the vanilla-like smoke of sweet grass to treat certain health conditions, including common colds. In addition, they also burn the grass to repel insects. The leaves of this herb are used to prepare a tea that is traditionally drunk to cure sore throats, coughs, fever as well as venereal diseases. Occasionally, this herb has also been employed to end uterine bleeding as well as to get rid of the afterbirth following childbirth.

There was a time when extracts obtained from the herb or decoctions prepared from it were employed to wash the hair and body. People also used sweet grass in the form of a body-rub. Alternately, they also used sweet grass to weave into their hair, as the plant has a pleasing aroma.

There were many who used this aromatic grass to pack their pillows and mattresses, while they weaved the dried up leaves of the plant into their fabrics so that they smelled good. In addition, the native tribes in North America used the long leaves of sweet grass to weave baskets as well as mats. Baskets and mattresses woven with sweet grass leaves retained the vanilla-like aroma of the plant for many years.

Earlier and even today, many indigenous groups of North America consider sweet grass to be a holy plant and have been using it in the form of incense in nearly all their sacred rituals, healing practices, purification processes, initiations as well as peace ceremonies. They believe that the vanilla-like sweet aroma of sweet grass smoke not only purified the spirit, but also brought holy messages to the elevated levels of existence. The native tribes of North America are of the view that the Nature (which they call as 'Wakan Tanka') is able to understand the messages sent by them through the sweet grass smoke better than those which were spoken in the form of prayers and hymns.

Sweet grass was also used for a variety of therapeutic purposes, including in the form of a solution for eyewash. It was also used for treating problems, such as chapping and windburn.

Alternately, the Native Americans mixed sweet grass with Thalictrum occidentale (commonly also known as western meadow-rue) seeds for preparing an herbal tea, which was drunk to clear nasal congestions.

The Karok people inhabiting the northern regions of California use a particular sweet grass infusion for treating women suffering from miscarriage. It was said that drinking this grass infusion also facilitated in arresting the growth of the fetus in pregnant women.

In addition to its use in herbal medicine, sweet grass is also employed in aromatherapy. As the plant has a sweet aroma, it is used in the form of incense. The smoke of the burning dried sweet grass is also known to help in meditating.

Habitat and cultivation

Hierochloe odorata or sweet grass is a rhizomatous plant that grows perennially. This plant is indigenous to the comparatively cool regions of Europe and North America. It is found growing naturally in damp, cool pastures, cool mountain canyons and in the shaded banks of streams.

In its indigenous environment, sweet grass is found growing mostly in the riparian areas as well as wetlands. In fact, it is not right to harvest the plants growing in the wild, as wetlands are becoming increasingly rare all over the United States. Harvesting of the wild plants should be limited to just recovering this species and that too only after obtaining proper permits or approvals. It is indeed worrying that the populations of sweet grass are decreasing rapidly owing to harvesting of the plants for personal as well as commercial use. It is worth mentioning here that the existence of this species is dependent on excessive collection and it is also susceptible to grazing.

It is possible to propagate this species in a container very easily from its bare rootstock, which produces numerous rhizomes. In addition, sweet grass can also be propagated from its seeds. Nevertheless, in the wild, sweet grass produces seeds sporadically and even the rate of germination of these seeds is somewhat poor, just about 25% to 30%. Therefore, it is more difficult to propagate this plant from its seeds compared to propagation from the division or cutting of the sweet grass plants.

As the rate of germination of sweet grass from its seeds is quite low and its survival is at stake in many places, the plant requires much commitment as well as attention while you are handling it. Plenty of care should be taken for the satisfactory survival of the plants. In the initial stages, it is advisable to keep the plants in the containers for extra two to three weeks after receiving them. In addition, you should water the young sweet grass plants daily while they are being grown in the containers. These are necessary as the probability of protracted transplant shock as well as owing to the fact that the soil in the containers becomes arid quite quickly. The growth of the plants will continue and they will thrive well in the original pot for some time till the time you finalize the site where you desire to transplant them and prepare the site appropriately.

You need to be extra careful while selecting the site where you want to transplant the young sweet grass plants. In addition, it is essential to prepare the site appropriately prior to transplanting the plants. Ideally, you ought to keep the area just adjacent to the planting site clear from any other plant that may try to compete with sweet grass. In other words, you may require undertaking weeding activities manually around each plant or use mechanical means wherever necessary. In its natural environment, sweet grass grows in wetlands and, hence, you may require irrigating the land while transplanting the young plants outdoors from the pots. To ensure the satisfactory survival of the plants, it is important to keep the soil very damp or moist.

If you have collected the plants from the wild or have initially grown them in a greenhouse, you should dig up the plants and separate them sometime during the end of fall or in winter. In fact, this is the period when the plant lies dormant after its seeds mature and the leaves become senescent (dry up and their color changes from green to brown). While separating the plants, make sure that all the individual plants either have a rhizome or rhizome buds. Take special and individual care while transplanting the plants. They should essentially be planted in a loose soil and a place that receives full sunlight. Each plantlet ought to be planted three feet away from each other; when they grow up, they will fill the vacant space and turn out to be solid sweet grass strands in one or two years' time. Ensure that the plants remain moist all the time and water them often. You may require protecting the young plants from intruding herbivores like gophers or rabbits. In fact, even dogs have a liking for sweet grass and will particularly eat the shoots of the plants and also roll on the grass, damaging the growth of the plants.

Side effects and cautions

Sweet grass contains a compound known as coumarin, which is a naturally occurring anti-coagulant and also provides the plant with its pleasing aroma. However, if you take coumarin internally in excessive amounts and for a prolonged period, it may result in liver damage as well as hemorrhages. It has also been found that coumarins are carcinogenic (cancer causing agents). However, when this herb is used in the form of incense during ceremonies, it does not cause any harm.

Collection and harvesting

Sweet grass is harvested in the same manner as you cut grass. The harvesting of this plant is done during the period between early and late summer. The grass is cut to one's desired length. However, if you harvest sweet grass following the first frost in your area, it will have very insignificant or no aroma at all. Sweet grass harvested during this period is less in demand for basketry. After harvesting sweet grass, basket weavers dry the plant in sunlight till it becomes completely dehydrated and delicate. When sweet grass becomes dry and brittle it should be kept immersed in warm water till it becomes flexible. The pliable sweet grass is usually woven or plaited to form thick threads and subsequently dried once more for use.


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