Revised 7/00 -- Author Reviewed 7/00 HIL-131
Introduction
Goldenseal (Hydrastis
canadensis L.) is a highly valued medicinal herb which has been
collected from the forests in North America for hundreds of years.
The historical range for goldenseal in the United States was very
broad, ranging from as far north as Vermont and Wisconsin, south to
Alabama and Georgia, and west to Kansas. It can still be found
growing in patches in moist, rich, hardwood forests in much of this
area. The core of the range now appears to consist of Illinois, Ohio,
Indiana, and eastern Kentucky. Over the years, goldenseal has been
referred to by a large number of other names, including yellowroot,
ground raspberry, yellow puccoon, wild circuma, eye-balm, yellow
paint, wild turmeric, and yelloweye.
Unfortunately, high demand for goldenseal has caused a serious reduction in native populations. As early as 1884, dramatic declines in wild populations due to overharvesting and deforestation were documented. In North Carolina, goldenseal is an endangered species, making harvest from public lands illegal. In 1997, goldenseal was listed on Appendix II of the Convention for International Trade on Endangered Species of Wild Fauna and Flora (CITES), an international treaty monitoring trade in threatened and endangered species. This listing imposes controls on goldenseal trade designed to protect the species and encourage sustainable use. This has not stopped people from collecting it, however, and populations continue to decrease. Fortunately, cultivation of this herb is fairly easy.
Regulations
Because of its endangered
status in North Carolina, permits from the N.C. Department of
Agriculture and Consumer Services, Plant Protection Division are
required to cultivate or propagate goldenseal within the state.
Permit applications can be obtained by contacting the N.C. Department
of Agriculture and Consumer Services, Plant Conservation Program,
P.O. Box 27647, Raleigh, NC 27611. Phone number 919-733-3610. You
must obtain a CITES permit or certificate before you can export
cultivated or wild-collected goldenseal roots or parts of roots. You
will need to show that roots, rhizomes, or seeds came from legally
acquired parental stock and that the plants were cultivated for four
years or more without augmentation from the wild. For permit
applications or more information, contact the Office of Management
Authority, 4401 N. Fairfax Drive, Room 700, Arlington, VA 22203.
Phone 1-800-358-2104 or visit the website at http://www.fws.gov/r9dia/
for more complete information.
Uses
The medicinal properties of
goldenseal are attributed to the alkaloids hydrastine and berberine
which are present in concentrations of 2 to 10%. Cherokee Indians used
the bitter tasting root of goldenseal for many purposes, e.g., as an
antiseptic, a general health tonic, and to treat snakebite. Iroquois
Indians used it to treat whooping cough, pneumonia, and digestive
disorders. Early American pioneers used it primarily as an eyewash
and to treat sore throats, mouth sores, and digestive disorders.
Commercial demand for the root began in about 1860. It is now a top
selling herb in North America and can be found in many formulations
in stores across the country. Current uses include treatment of nasal
congestion, mouth sores, eye and ear infections, and as a topical
antiseptic. It is commonly believed to help boost the immune system
and increase the efficacy of other medicinal herbs. Some people also
mistakenly believe that goldenseal will mask urine tests for illegal
drugs.
Plant Description
(Family-Ranunculaceae,
Subfamily-Hydrastiodoideae). Goldenseal is a herbaceous perennial
which emerges in early spring (mid-March to early May) from buds that
overwinter on the perennial rootstock. The root system is composed of
a bright yellow, horizontal rhizome,
1/2 to
3/4 of an
inch thick, marked by cup-like depressions where the annual stem
falls away. The rhizome is covered with a mass of bright yellow
fibrous roots and rootlets. Mature plants (at least 3 years old) are
6 to 14 inches tall and have two or more erect hairy stems usually
ending in a fork with two leaves. The 5 to 7 lobed, palmate,
double-toothed leaves are 3 to 12 inches wide and 3 to 8 inches long.
After emergence in early spring, flower buds quickly develop and
small, inconspicuous, white flowers open as the leaves unfold. Plants
started from seed usually flower when 3-4 years old whereas
vegetatively propagated plants may flower the first year. Each plant
can produce a single, green raspberry-like fruit which turns red and
ripens in July. Goldenseal spreads into the surrounding area through
growth of the rhizomes and fibrous roots. Usually two buds form near
the base of the stem on the rhizome for the next season's growth. The
plant dies down slowly after the fruit matures.
Cultivation
Goldenseal has been cultivated
since the early 1900's and many of the current recommendations for
growing goldenseal are surprisingly consistent with those found in a
1914 U.S.D.A. Farmers' Bulletin. The best success with goldenseal
will probably be obtained in areas where goldenseal is native.
Success in other areas will depend on how well those conditions can
be duplicated.
Site Selection
Site selection is the most
important factor for producing healthy goldenseal. Goldenseal grows
best in a rich, moist, loamy soil with good air and water drainage.
Planting on a slight slope will improve drainage. Do not plant in a
bottom or in a heavy, poorly drained soil. If growing in the forest,
look for a site where there are other woodland plants growing such as
mayapple, trillium, bloodroot, and black cohosh. Do not select a site
where there is no undergrowth because it is probably too dark for
goldenseal. Conversely, try to avoid sites where the undergrowth is
particularly thick, such as in a rhododendron thicket, for the effort
required to remove the plants and their roots would be too costly. A
site with mixed, deeply rooted hardwoods is preferred to a solid
stand of conifers or other shallow rooted trees which can compete
with the goldenseal for moisture and nutrients. Plantings established
under oak, poplar, walnut, and basswood have been successful.
If growing under artificial shade in an open field situation, it is important to choose a site with few weeds or to control the weeds before planting. Grasses can be a very big problem if planting into a pasture without adequately turning the soil to kill existing weeds and seeds.
Do not plant in an area known to be infested with soil-borne diseases, especially Rhizoctonia. Also, to reduce the risk of disease, do not replant goldenseal immediately after a crop of goldenseal.
Shade
Goldenseal needs to be grown in the shade, which can be
provided artificially or by a natural forest canopy. Artificial shade
can be provided by a wood lath structure, a polypropylene shade
structure, or by vining plants growing over a support. In a study in
progress in western NC, four levels of shade are being evaluated. To
date, the best plant growth has occurred under 63% to 80% shade.
Plant stand counts and survivability have been highest under 47% and
63% shade. The influence on root growth will not be determined until
fall 2000.
When designing the shade structure or preparing an area in the forest, provide for adequate air circulation. For artificial shade, make the structure 7 ft tall or higher with two ends open to the prevailing breeze. For forest culture, select a site with good air and water drainage in an area shaded by tall, preferably hardwood, trees.
Site Preparation
In a woodland site, remove small, undesirable trees, tree
roots, weeds, and other undergrowth. In all cases, till or turn the
soil and amend, if necessary. To promote good water drainage and to
warm the soil early in the spring, raised beds should be constructed.
Beds should be 2 to 6 inches tall and 3 to 4 ft across. Leave
sufficient space between beds to allow for easy walking, pushing a
wheelbarrow, and kneeling for weeding and picking fruit.
Soil Amendments
Several months before planting, collect soil samples for
fertility testing and nematode assays. For most soil testing
laboratories, it will be necessary to identify the crop as "native
ornamentals." If soil tests reveal low organic matter at the planned
site, increase it through addition of compost. In a study conducted
on forest soil in western NC, goldenseal produced the highest root
yield when grown in soil amended with 2.7 to 5.2 tons of lime/acre
which resulted in a soil pH of 5.5 to 6.0. In this same study, plant
survival and root yields decreased as nitrogen (supplied as ammonium
nitrate) rate increased. The addition of superphosphate had no effect
on plant survival or growth. Based on these results and grower
experiences, on a high organic matter soil goldenseal should only
receive light fertilization, preferably from an organic source.
Sandier soils will require more. In all instances, a balanced
fertilizer can be applied at a low rate each spring as growth
commences. Some people are reporting positive growth responses to
high applications of calcium in the form of gypsum. Preliminary
results from studies on the influence of gypsum on goldenseal at the
Mountain Horticultural Crops Research Station, however, did not
support these observations. In our studies, gypsum applied at 2000 to
5000 lb of calcium per acre, resulted in reduced leaf number and leaf
size, increased disease incidence and earlier dieback compared to
plants grown in soil without additional calcium.
Propagation
Goldenseal can be propagated from rhizome pieces, root
cuttings, one year old seedlings, or seed. It takes 5 to 7 years to
grow harvestable roots from seed and 3 to 5 years to grow harvestable
roots from rhizome pieces. Root cuttings or seedlings usually take 4
to 6 years. Fall planting has been successful in all growing areas.
Spring planting has also been very successful in the Southeast. In a
recent study, goldenseal planting stock (rhizomes with roots or one
year old seedlings) held at 400
F until planting in early July experienced no ill effects as a result
and could not be distinguished from the spring planted material by
the following season.
Vegetative Propagation
Goldenseal can be vegetatively propagated by dividing
rhizomes into 1/2
inch or larger pieces (2 to 5 grams). Each piece should have healthy
roots and, ideally, a bud. Research showed that pieces as small as
one gram would produce a plant, but it greatly extended the time to
root harvest. In that same study, the presence of roots on the
rhizome piece proved to be more important for plant survival than the
presence of a visible bud.
Another method of vegetative propagation, called layering, involves removing two inch sections of the strong fibrous roots exhibiting buds or even just a swelling and layering them under one inch of soil or chicken grit in a nursery bed in early spring. The root pieces, which should form buds during the summer, can be planted into production beds the following autumn. Although several growers have reported success with this method, the author has not.
Rhizome pieces, seedlings, and layered plants should be planted in narrow trenches about 2-3 inches deep. Place the planting stock in the trench with the bud facing up and bury with soil. It is common practice to plant goldenseal on a 6 inch x 6 inch spacing. In an effort to optimize production per unit land area, spacing studies are currently underway. Spacings ranging from 2 inch x 2 inch to 12 inch x 12 inch are being tested.
Seed Propagation
Propagation of goldenseal from seed can be difficult with
unpredictable results. Germination rates of purchased seed, which has
usually been stored in moist sand in a cooler or buried in the soil,
can range from 0% to 90% the first spring after seed harvest. In an
effort to develop methods to obtain reliable germination rates, seed
handling studies have been in progress at the Mountain Horticultural
Crops Research Station for several years. In the first study, we
found that the best germination rates the first spring after seed
harvest were obtained when seeds were quickly extracted from the
fruit using a sieve method. The seeds were then stored in moist sand
at 700
F until sowing in late fall. This treatment resulted in an average
germination rate of 37% (range 25% to 88%). For many of our
treatments, seed did not germinate until the second season after seed
harvest. The highest germination rates the second season were from
seed that were extracted from the fruit by the sieve method, held at
700 F for
30 days followed by 400 F
until planting or held at
400 F.
In both cases, the seed were planted the spring after seed harvest
and germinated two seasons later. Average germination rate with this
method was 45% (range 30% to 71%).
Seed Collection and
Stratification
Although studies are currently in progress to determine the
best methods for seed handling, within the industry the most popular
method is as follows. To collect seed from goldenseal, harvest fruit
when fully ripe (red). Mash the fruit by kneading, being careful not
to damage the seed, and ferment in water until the flesh can be
easily removed from the seed. This usually takes several days. Add
water, decant, and rinse until the water and seed are clean.
Alternately, spread the seeds out on a fine-mesh screen and spray
with a high pressure stream of water. For the large-scale producer
there are seed cleaners available that will do all this in one step.
Goldenseal seed are small, round, black, and hard. Like ginseng seed,
they should never be allowed to dry out. If the seed will not be sown
immediately, the most common way to handle it is to mix it with fine,
clean, damp sand and place it in a screen pouch or a wooden box with
a fine-mesh screen top and bottom. Bury in a shaded, well-drained
area exposed to natural rain. If the weather has been very wet or
dry, after two weeks, uncover the box and ensure that the sand is
damp and not waterlogged. The seed can be planted in late fall or
early spring.
Seeds are best planted in a nursery bed. Sow 10 to 12 seeds per ft in rows three inches apart with seeds 1/2 inch deep. Use of a mechanical seeding device is recommended. Cover lightly with a mulch to prevent drying of the soil. Goldenseal seed is most commonly sown in the fall. It can also be planted in the spring, but it must be done very early and handled very gently because some of the seed will certainly have germinated by that time.
Mulch
Goldenseal should be mulched to hold in soil moisture,
reduce weed growth, moderate temperatures, and provide winter
protection. The mulch layer should be several inches deep at time of
planting. Depending on the type of mulch, it may need to be
replenished every year or two. In areas where the soil tends to
freeze and thaw, several inches of extra mulch should be provided to
protect the roots during the winter. The mulch should be raked back
to a depth of 1 to 2 inches before the plants emerge in the
spring.
Goldenseal is commonly mulched with whole or shredded leaves, hardwood bark chips, hardwood bark and sawdust mixture, or straw. Although straw is used successfully in many areas of the country, in studies at two locations in NC straw has performed poorly. The straw tends to hold excessive moisture near the crown of the plant causing rot. Slugs have also caused significantly more damage in the straw mulched plots than in any other mulch treatment. In two years of growth, hardwood and pine bark mulches have performed well. Plants grown with a fresh sawdust mulch were nitrogen deficient the first year but grew well the second year.
Irrigation
When grown under a forest canopy, goldenseal rarely, if
ever, requires irrigation. Under drought conditions, however, if not
irrigated the plants will drop their foliage and go dormant earlier
than usual. This usually does not harm the plant, but will reduce
root growth for that year. If that loss is not acceptable, site
selection should include consideration of how to irrigate if
necessary.
Pests
Under natural conditions and when grown in small, isolated
plots in the woods, goldenseal suffers few attacks from diseases or
insects. The major problem in many small plots in the Southeast is
slugs which can eat the entire crown of the plant and fruit. Slug
control can be difficult and successful methods are often site
specific. Control methods that have been successful at some sites
include using beer traps, spreading diatomaceous earth (must be
replaced after every rain) or a mixture of lime and woodashes around
the plants, or applying a commercially available slug and snail bait.
If the populations of slugs are intolerable, it may be necessary to
remove the mulch from around the plants. Moles and voles may also
damage the beds and should be controlled with traps or by bordering
the beds with wire mesh set 8 to 12 inches deep in the soil.
If the field is properly prepared and the beds mulched adequately, weeds are not often a serious problem. They can usually be managed by hand weeding several times during the season.
Root knot nematodes will severely reduce growth and root yield of goldenseal. Soil should always be tested for their presence before planting, even in a forest setting.
Five years ago, the only disease commonly reported on goldenseal was botrytis leaf spot. Removal of the affected foliage and the mulch in heavily infested areas, has provided reasonable control. As more and more goldenseal is cultivated on a large scale in the U.S. and Canada, there have been increasing reports of disease. Most of these diseases, however, have occurred under artificial shade structures, not in the forest. Diseases known to attack cultivated goldenseal in recent years include alternaria, rhizoctonia, and fusarium. In artificial shade structures, there may be some problems with damping-off in areas where there is excessive drip from the structure, as under joints and seams. There has been an unconfirmed report of phytophthora root rot. In North Carolina, however, goldenseal has been grown successfully in old ginseng beds known to be infested with Phytophthora cactorum.
Harvest
When goldenseal plants have fully occupied the land they
were planted in, usually in 3 to 5 years, either harvest the roots or
divide the plants. If left undisturbed, the plants will start to
crowd themselves out and the oldest roots will eventually die. Dig
roots in the fall after the tops have died down. If a market exists
for the leaves and stems, harvest them in early autumn while the
foliage is still green. Dig roots carefully, keeping the many fibrous
roots intact. Small plots can be dug with a fork. Large fields will
require some kind of mechanical digger. Modified potato, horseradish,
and bulb diggers have been used. Select large, healthy plants for
replanting and have a container available to keep them moist and cool
or have beds prepared to replant immediately.
Washing and Drying Roots
Carefully wash the remaining roots by spraying with a hose
over a large-mesh screen. Remove all dirt, breaking larger roots if
necessary, but do not use a brush. There are commercial ginseng root
washers available that consist of a drum that turns and tumbles the
roots as water is sprayed over them. Simple root washers can be
easily constructed.
Spread the clean roots on screens and dry in a well-ventilated area in the shade or in a forced air drier. Simple driers can be constructed from small sheds or rooms in barns. Bulk tobacco barns can also be modified to successfully dry goldenseal roots. The key points are to keep temperatures low, around 95 to 1000 F, and to provide good air flow around the roots. If the roots are dried too hot and fast, the outside of the root dries first, leaving the inside of the root moist. It is then very difficult to extract moisture from the interior of the root. The quality of the roots is then destroyed and the roots will bring a substantially lower price than properly dried roots. Roots will lose about 70% of their weight during drying. Test for dryness by breaking a large root; it should snap cleanly but not be brittle.
Yields and Packaging
Good yield estimates for goldenseal are not currently
available due to the tremendous differences among growers in amount
of planting stock used, plant spacing, bed and row spacing, and years
to harvest. Most commonly reported yields for artificial shade
structures are 1000 to 2000 lb of dried root per acre. Yields as low
as 800 lb per acre and as high as 3000 lb per acre have been
reported. Dried roots should be packed loosely into cardboard cartons
or barrels, clean, untreated burlap sacks, or poly-sacks. Store in a
cool, dry, dark area secure from insects and rodents.
References
Foster, S. 1991. Goldenseal Hydrastis canadensis.
Botanical Series No. 309 American Botanical Council, Austin,
Texas.
Haage, L.J. and L.J. Ballard. 1989. A grower's guide to goldenseal. Nature's Cathedral, Norway, Iowa.
Hardacre, J.V., G. Henderson, F.B. Collins, E.L. Andersen, V.M. Harris, B. Fewster, R. Beck, D. Bowman, and E.L. Donzelot. 1962. The wildcrafters goldenseal manual. Wildcrafters Publications, Rockville, Indiana.
Lloyd, J.U. 1912. The cultivation of hydrastis. J. American Pharmaceutical Assoc. 1:5-12.
Van Fleet, W. 1914. Goldenseal under cultivation. U.S.D.A. Farmers' Bulletin #613.
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Published by the North Carolina Cooperative Extension Service |