arnica montana a grower s guide for commercial production...

Crop & Food Research Report No [Click and type report number here]

Arnica montana a grower‟s guide for commercial production in New Zealand.

B.M.Smallfield & M.H. Douglas

December 2008

A report prepared for

New Zealand Arnica Growers‟ Group

New Zealand Institute for Crop and Food Research Limited Private Bag 4704, Christchurch, New Zealand.

© 2008 New Zealand Institute for Crop and Food Research Limited

Arnica montana a grower,s guide for

commercial production in New

Zealand.

B.M.Smallfield and M.H. Douglas

Disclaimer: The New Zealand Institute for Crop & Food

Research Limited has exercised reasonable skill, care and

diligence in producing this grower guide. It contains general

information only and is not exhaustive on any topic. It is

therefore not intended as a substitute for professional

advice. The Institute cannot accept responsibility for

consequences of actions arising from the use of the

information contained in this publication.

Cover Photo: Arnica montana Variety Arbo in flower 29th Jan

2006 on MAF SFF arnica trial at 600 masl. Styx Creek,

Central Otago. Source: Pauline Seaton.

Contents

1 Introduction 5 1.1 What is arnica? 5 1.2 Objective of this growers‟ guide 2

2 How is arnica used? 3 2.1 Active constituents and quality standards 3 2.2 Traditional source of flowers 6

3 Requirements for growing arnica flowers 6 3.1 Environmental fit 6 3.2 Plant Propagation 6 3.3 Field Establishment 7 3.4 Planting density 8 3.5 7 Weed control 9 3.6 Pests and Disease 11

4 Flower Production 12 4.1 Time of flowering 12 4.2 Effect of Flower maturity on Quality 12 4.3 Flower Harvesting and post harvest handling 12 4.4 Flower Yield and returns 14 4.5 Crop improvement Error! Bookmark not defined.

5 Acknowledgements 14

6 Sources of Information 14

1 Introduction

1.1 What is arnica?

Arnica (Arnica montana L.) is a rhizomatous

herbaceous perennial herb of the daisy family.

The broad spear shaped leaves form a flat

rosette (about 150-300 mm high) and die

down in winter. A flower stalk (20-60 cm high)

rises from the rosette with a number of bright,

orange - yellow daisylike flowers, about 4-8

cm wide. The flowers open progressively

down the flower stalk with the terminal bud

normally producing the largest flower. The

rhizome is dark brown and cylindrical. Usually

curved, it bears leaf scars and on the under

surface wiry rootlets.

The word arnica comes from the Greek “arnakis”, meaning lamb‟s coat, and refers to

the felt-like sepals covered in soft hairs that surround the flower. Arnica montana is

commonly called European arnica or mountain tobacco. It grows wild across Europe

from southern Norway and Latvia southward to Portugal, and east across Europe to the

north Appennine mountains in Italy and south Carpathian mountains in Romania. A

subspecies commonly called Spanish Arnica or Bolós (Arnica montana subsp.

atlantica) is restricted to an area of south-west France the Gallica region of Northern

Spain and into Portugal. Arnica grows naturally on low fertility meadows, peat bogs

heathlands and alpine meadows on acid soils, between 500 and 2500 m in altitude, but

is now a threatened species over most of its natural range.

A niche high value pharmaceutical and medicinal herb, it is used as fresh whole plants,

dried flowers or dried roots. Collection from the wild is often undertaken by Romany

gypsy communities and then traded through dealers and brokers. The pharmaceutical

and medicinal trade names for the dried flowers are Arnica flos (Latin), Fleur d‟Arnica

(Fr), Flor de árnica (Sp), Arnikablüten (Ge) and Fiore de arnica (It) and the trade names

for dried root are Arnicae radix (Latin), Racine d‟Arnique (Fr), Raiz de árnica (Sp),

Arnikawurzel (Ge).

Arnica montana plant in flower.

Crop & Food Research Report No

1.2 Objective of this growers‟ guide

There is growing international demand for arnica as an ingredient in medicinal,

physiotherapy and sports massage products and in a growing range of cosmeceutical

and personal care products. Most of the world production of dried flowers is however,

still dependant on wild sources. The abundance of arnica has greatly declined in the

wild over much of Europe, due to loss of habitat, changing ecological conditions and

over-harvesting for medicinal purposes (Lange 1998). Aerial fertilisation as a result of

air pollution is also threatening the survival of wild arnica. Legal conservation

protection measures are now in place throughout much of Europe. As demand for

arnica continues to rise, cultivated arnica will increasingly be looked on to supply this

demand.

New Zealand has a good opportunity to commercially cultivate arnica flowers and roots

for the international markets. Trading on its reputation for high quality and its natural

„clean green‟ image in Europe, is an advantage for promoting medicinal herb products.

Arnica was first identified as a potential new crop for Otago when the Dunedin

Botanical gardens were first established in 1863 (Dunlop 2003). Research resumed in

New Zealand in the late 1980‟s and significant progress has been made towards

defining arnica‟s key quality constituents, and agronomic and environmental

requirements in a temperate climate. This booklet aims to give potential growers and

primary processors information on growing the crop in the Southern South Island.

Recent research results are summarised and costs and potential returns are presented.

Crop & Food Research Report No Page 3

2 How is arnica used?

Wild-harvested Arnica montana flowers, roots and the whole plant have a long history

of use as a herbal medicine with flowers being the most important. Arnica heads the

list of phytotherapeutic remedies with as many as 271 preparations (Bisset 1994). The

most frequently used form of the herbal medicine is as a tincture, prepared from 1 part

dried flowers and 10 parts 70% ethanol (Bisset 1994). An arnica oil extract is

traditionally prepared from 1 part of dried flowers and 5 parts vegetable oil with an

ointment containing a maximum of 15% arnica oil. Preparations derived from the dried

flowers are topically applied to reduce the swelling and pain from bruises, sprains,

fractures, rheumatic and joint problems, chilblains and insect bites. The active

constituents have been shown to have strong anti-microbial, anti-inflammatory, anti-

rheumatic, anti-arthritic and anti-hyperlipidaemic properties. They also affect the heart

and circulation. It should not be used for prolonged treatment of damaged skin and

long use can also give rise to eczema. Arnica has also been shown to contain

sensitising agents that may act as allergens in a proportion of the human population.

Internal use should be very carefully controlled or avoided, owing to the toxicity of the

sesquiterpine lactones. In Germany it is used for heart conditions. A prescription from

a qualified practitioner is required for internal use in the United Kingdom and in the

United States it is regarded as unsafe for internal use.

2.1 Active constituents and quality standards

The main chemical constituents responsible for its pharmacological properties are the

sesquiterpene lactones (SL), helenalin and dihydrohelenalin, and their short chain

esters. These are thought to be produced in the glandular trichomes that cover the

surface of the leaves, stems, flowers and seed coat. European arnica contains

principally the helenalin esters where as the subspecies Spanish arnica contains

predominantly dihydrohelenalins and only small amounts of the helenalin esters. There

is some evidence that suggests that helenalins and dihydrohelenins may differ in their

antiinflamatory efficacy and their allergenic side effects, but clinical studies are still

required. The active compounds are extracted by alcohol or vegetable oil and have

been reported at levels ranging from 0.3 to 1% total sequeterpine lactones in flower

heads and at much lower levels in leaf and stem material. New Zealand grown arnica

has total SL levels of 0.66% to 0.94% (Douglas et al 2004), within the same range and

composition as found in Europe and well above a 0.4% suggested minimum standard.

New Zealand research has shown that the level of SL increases as the flower head

matures (Doulgas et al 2004). The SL composition of the arnica flowers also appears

to be most strongly influenced by plant genetics and not affected by growing

environment. The analyses of dried arnica flowers of the Arbo variety harvested from

the MAF SSF arnica trials in 2006-07 season showed SL composition was very similar

at all sites (Table 1). Results from Crop & Food Research plant selection trials also

indicates very little year to year variation in SL composition of arnica flowers.

The plants also contain 0.2-0.35% essential oil. Dried flowers must also meet

quantitative standards for foreign matter (generally not more than 1%), moisture

content (not more than 9 %), total ash not more than 8-9%, maximum counts for yeasts

and moulds, not more than 1% stem and receptacles with attached involucre of not

more than 25-33% (Bisset 1994). Each consignment is also examined macro and

microscopically to confirm botanical authenticity and for presence of adulterants. Many

companies are also actively looking to source spray free or organically certified product.


Glandular trichomes on the leaf surface of young arnica plants

0

5

10

E F G H

Tota

l S

L (

mg/g

)

Effect of flower maturity on total sequiterpene lactone content (Douglas et al 2004).


Table 1. Effect of location of the Sesquiterpene lactone composition and total SL content of dried arnica flowers

(plant variety Arbo), 2006 .

Location

SL Compounds Methven Weston Waipiata Styx Creek Three Mile Hill Invercargill

Dihydrohelenalin (%) 2.12 3.29 3.80 3.26 4.92 4.91

Helenalin (%) 1.09 1.28 1.01 1.90 1.68 1.37

Acetyl Dihydrohelenalin (%) 1.96 2.52 3.02 3.21 3.11 3.32

Acetyl Helenalin (%) 5.78 6.59 10.36 8.64 8.07 9.61

Methacryloyl Dihydrohelenalin (%)

2.91 2.13 2.88 2.62 2.50 2.03

Methocryloyl Helenalin / Isobutyryl Dihydrohelenalin (%)

20.40 17.66 22.79 17.00 18.82 18.86

Isobutyryl Helenain (%) 19.69 24.87 18.60 18.98 18.60 19.31

Tigloyl Dihydrohelenalin (%) 2.92 2.68 2.54 3.35 2.59 2.04

Tigloyl helenalin (%) 14.28 12.12 14.34 14.40 14.86 13.44

2 Methyl Butyryl Dihydrohelenalin (%)

1.26 1.37 1.16 1.23 0.00 0.73

Iso Valeryl Dihydrohelenalin (%) 1.28 1.41 1.31 1.74 1.62 1.17

2 Methyl Butyryl Helenalin (%) 19.75 17.95 15.52 18.28 17.78 17.35

Iso Valeryl Helenalin (%) 6.55 6.13 2.66 5.39 5.46 5.85

Total SL content (mg/g) 11.48 9.44 8.70 7.67 6.37 7.25


2.2 Traditional source of flowers

Currently the major source of arnica flowers to the medicinal herb industry is harvested

from the wild in the Balkans, Romania, and Spain. An estimated 50 t of dried flowers

are traded annually in Europe (Lange 1998). This equates to 250-350 t of fresh

flowers. In New Zealand the annual demand is currently between 1.5 and 3 t of dried

flowers. New Zealand companies wish to source locally grown product because of the

increasing difficulties they face sourcing supply from Europe and problems with

adulteration. In addition small quantities of dried root and whole fresh plant are

consumed each year in Europe mainly for use in homeopathic preparations. This

material generally comes from cultivated sources.

3 Requirements for growing arnica flowers

3.1 Environmental fit

The environmental requirements to grow arnica in New Zealand are still not clearly

defined. Arnica is an alpine plant, but in New Zealand survives and flowers well under

cool lowland conditions. We have found from experimental sites at Hamilton, Hastings

and Lincoln the majority of plants failed to produce flowers over three successive

seasons and attributed the lack of flowering to insufficient chilling. The majority of

plants in grower trials at Methven, Rolleston and at 700 m on Banks Peninsula have

consistently produced flowers. Plants also failed to flower over two successive

seasons at a trial site near Westport. Our experience to date suggests the best

environments for growing arnica are the cool and moist regions of Otago and Southland

and possibly up against the foot hills on the Canterbury plains in the area covered by

the NW rain band. In these environments flower yields have been consistent over

several seasons and the plants are generally less susceptible to crown rot disease

problems. Plants have also flowered extremely well in trials on the Otago uplands at

Lee Stream and near Styx Creek at 600 m on the Rock and Pillar Range. The first

season flower yields (2006/07 season) at the Rock and Pillar site were the highest we

have recorded for the cultivar Arbo, averaging 700 kg/ha of dried flowers compared to

less than 200 kg/ha at four other sites. In the next season however, the flower yield

was very poor, possibly because of the effects of a severe drought restricted plant

growth from the conclusion of flowering at the end of January 2007 until the first snow

stopped all growth for the season.

3.2 Plant propagation

Plants are propagated from seed or by division. Arnica seeds are cylindrical in shape,

with a thousand seed weight of 0.9 to 1.3 g. Seed germination can be highly viable, but

is generally less than 80%. The seed is generally only available from specialist herb

seed suppliers in Europe and North America and current seed prices vary from $2000

to $6000/kg. Arnica seed can be imported into New Zealand without a permit, but any

importation of seed for sowing must meet the conditions laid out in the “MAF Standard

155.02.05 Importation of seed for sowing” (http://www.biosecurity.govt.nz/files/ihs/155-

02-05.pdf). Arbo is currently the only named cultivar of Arnica montana. Developed in

the 1980‟s in Germany the seed of Arbo has been imported into New Zealand from the

German licence holder by Crop & Food Research and the NZ Arnica Growers‟ group

for use in the MAF Sustainable Farming Fund Trials.


We have not attempted direct paddock seeding of

arnica because of the lack of synchrony in seed

germination, the low germination percentage of seed

lines plus the cylindrical seed shape makes

mechanical sowing difficult. The preferred method of

establishment for large scale planting is to raise plants

from seed under nursery conditions and transplant into

the field. Arnica plants can be propagated by

scattering the seed onto surface of trays containing a

commercial seed raising mix and then covering with a

thin layer of fine basalt chip. Covering the sown tray

with a layer of newsprint paper helps to retain moisture

during the germination period. Under glasshouse

conditions in August - September (night temperature

10-12 °C; day temperature 20-25 °C), the seeds

germinate in about 14-20 days but germination can be

extremely erratic depending on seed source, quality

and seed treatment.

We have found that the synchrony of germination can be improved by soaking the seed

in tap water for 24 hrs under natural light. After soaking, the seeds can be sown

immediately or dried back and stored for a period. Seedlings are pricked out 2-3 weeks

after germination into cell trays or tubes containing a commercial potting mixture. We

use a free draining mix consisting of 7 parts fine bark, 2 parts peat, 1 part gravel and 1

part horticultural sand and with a slow release fertilizer added. We have also

established that Arnica plants are very susceptible to high soluble salt loadings in

potting mixes and soluble salt levels of commercial potting mixes should be monitored

before use. Under our conditions we also found it was unnecessary to sterilize the

potting mix or to add lime. As part of the MAF SFF project Paul Verdonk, Whitestone

Nurseries at Weston, successfully developed an organic seedling production cell

transplant system.

An alternative method of propagation, that avoids the manual pricking out stage, is to

sow directly into cell trays, sowing 3-4 seeds/cell, and after germination, thin to leave

only one seedling per cell. The thinned plants can be used to fill the blank cells. For

direct cell sowing, seed with a high germination percentage must be used to avoid too

many blank cells. In trials using treated seed with an 80% germination percentage, we

still had a 28% blank cells count, from sowing 3 seeds per cell. The pricked out

seedlings are initially slow to develop and on average 6-8 weeks growth will be needed

prior to transplanting in the field. At the planting out stage the seedlings will have 3-4

pairs of leaves in a rosette, and a firm root ball. More research is required before direct

seeding will be possible.

3.3 Field establishment

The field establishment of seedlings transplants is most reliable when carried out in

spring after the last frost. Late summer/early autumn establishment can be successful

where there is adequate rainfall or access to irrigation and the plants have sufficient

time to grow and get their roots established before the onset of the first frosts. A high

proportion of autumn transplants will flower in the following spring, so the time to first

flower production is reduced with autumn planting. However, flower yield will be lower

than for a spring planted crop, because plants will be smaller. Autumn planting in

environments with hard winter frosts is risky as the seedlings can be killed by the

effects of frost heave.

Arnica seedling in cell tray


Arnica is very sensitive to soil conditions, and its cultivation should be kept on well

aerated acid land, free of lime, and not too rich in phosphates and nitrogen. Our

experience is that Arnica will grow and produce well on a wide range of soil types from

silts to clay loams, in the cool/moist environment, but with adverse soil conditions (very

wet or very hot and dry) the plants die rapidly with fungal crown rot invasion.

We have only used transplants and have not attempted direct seeding because of

erratic germination. At the planting out stage the seedlings will have 3-4 pairs of leaves

in a rosette, and a firm root ball.

3.4 Planting density

Our research has shown the first

season flower yields are density

dependent but the plant rosettes

will expand as basal buds grow

and a dense ground cover is

achieved by the end of the second

year. The increased flower yield

from plant densities great than 20

plants/m2, is unlikely to cover the

additional costs of the plant

material and establishment. The

risk of plant diseases spreading is

also higher with high plant

densities.

The transplants are best established in 150 cm wide, 4 row beds, with plants at 25 cm

spacing in row and 25-30 cm between rows, and with a 50 cm laneway between beds.

This is equivalent to a plant density of 16 plants/m of bed or 90,000 plants/ha. At this

density, the first year flower yields are less than at higher plant densities (up to 100/m

of bed), but the maximum flower yield was achieved at this density in the second

flowering season. This bed layout also aids management of the crop as it provides

traffic lane ways for weeding, general crop management and flower harvesting without

needing to drive over the crop. We have obtained improved plant survival and flower

yield from establishing plants on raised beds on heavier soils, but for lighter and very

free draining soils flat beds are best. On large scale planting we find a group of 4 to 8

people can plant hand plant between 800 to 1000 plants per hour. With a two row

mechanical punch planter, three people plus a tractor driver can plant 3000 plants/hr.

For mechanical planting the third person is used to replant material that is misplanted

(falls on its side or upside down). For efficient mechanical planting the plants need to

be of uniform size and with not too much top growth plus the beds also need to be level

and with a fine tilth.

Raised beds of Arbo plants Mosgiel, 6 weeks after planting.


Plants can be highly variable in their rate of establishment. Some plants may not

develop daughter rosettes within the first six months and others will produce multiple

rosette. Weed control is therefore critical during this establishment period and in drier

areas irrigation maybe required. Under good conditions with progressive daughter

rosette development plants will reach a diameter in excess of 25-30 cm. From a spring

planted crop a percentage of plants may flower in the autumn of the establishment

year. The proportion of plants flowering appears to relate to when the crop was

established and autumn weather conditions. In the MAF SFF trials more plants

flowered in the first autumn at the cooler higher altitude sites than at the warmer

lowland sites.

The fertiliser requirement for the crop is dependent on the existing soil fertility, and as a

standard practice, the soil should be analysed for macro elements prior to crop

establishment, and any deficiencies rectified. We have found the plants will respond to

low to moderate applications of NPKS fertiliser but high levels of fertiliser in spring can

encourage crown rot disease.

3.5 Weed control

There are no herbicides registered for use on Arnica in New Zealand, therefore

planting into a stale seedbed (a seedbed which has had the weeds controlled before

planting and not re-worked) is prudent management. White clover and grass weed

invasion can be a significant problem and once established can quickly smother and kill

the crop. Control of weeds in the lane ways is also critical.

The SFF arnica protect investigated the effectiveness of several types of potential

organic weed methods for controlling weeds including a plant fatty acid herbicide, a

planting through a layer of wood chip mulch, a biodegradable corn starch film, a paper

mat material and synthetic woven weed cloth cloth. Herbicides composed of plant fatty

acids or pine oils can only be used for spot treatment of weeds under AsureQuality

Organic Standards. However, these types of products were not effective with arnica

because the temperatures required for good herbicide action do not occur when arnica

is dormant. The physical barrier systems also gave mixed results. At all sites the

paper barrier and corn starch film failed to survive the growing season. In most cases

both paper mat and the corn starch film material were ripped and blown off the beds by

the first strong NW winds. It would appear that the arnica plants do not establish

quickly enough to anchor these materials. Even though these materials did not survive,

retaining a barrier on the surface for a limited period of time did have some residual

effect on slowing the rate of weed invasion. The woven weed mat was found to provide

effective weed control at all sites. Under the weed mat and wood mulch the plants

Hand planting arnica at Weston and mechanical planting at Styx Creek.


were to be slightly larger and the barrier also conserved soil moisture under dry

conditions. The disadvantages of the weed mat are holes need to be cut in the

material, plants need to be planted by hand and at the start of the second season it

needs to be taken up or the size of the holes expanded to accommodate the growing

rosette. There is also a disposal issue with the synthetic woven weed mat at the end of

the products life. The corn starch film would offer significant weed control advantages if

a heavier grade of film was more resistant to wind damage. The film is cheaper than

woven weed mat, can be laid with a standard film laying machine and a planter can

punch through the film. The film has a 120 day life and is fully biodegradable. The

corn starch film is currently not certified for organic use in New Zealand.

Organic methods of weed control at Styx Creek site.

Organic Weed control treatments showing wind damage to corn starch film and white recycle paper mat at Three Mile Hill site, 16 December 06.


3.6 Pests and diseases

Arnica plants are very sensitive to crown rot and fungal diseases, the most serious of

which are Phytophthora and Phoma. During the growing season, individual or patches

of plants can collapse and die suddenly when conditions are unfavourable, particularly

under hot wet or hot dry conditions. The first visible symptom of the disease is that the

plant starts to wilt. There are no fungicides registered for use on arnica. Therefore good

plant hygiene techniques need to be maintained right through the production cycle.

We have found no value in replanting into infected areas as the new plants also often

succumb to crown rot. A proportion of plants taken out by the disease will re-grow from

a surviving piece of rhizome, but often they continue to have a chronic level of infection.

Further work needs to be undertaken to determine how best to manage this disease

plus selection for plant resistance would offer a significant advantage. Patches of

plants killed by disease also provide areas where weeds such as white clover can

establish and spread into and smother healthy plants if not controlled.

No major insect pest problems have been identified to date. The leaves are attacked by

the caterpillars of the magpie moth and the green looper, but damage is relatively

minor. Populations of grass grub larvae have also been found under mature plants but

there has been little evidence of feeding damage to the roots. Aphids can be an issue

on seedlings being propagated in the greenhouse, causing curling and distortion of the

leaf. In some other daisy species the SL‟s have been shown to have insecticidal

properties against some insects.

At several locations rabbits have caused minor damage,

digging up plants and leaving them littered on the soil

surface. At an experimental site near Outram, we also

experienced a problem with magpies pulling up thousands

of seedlings, within 24 hrs of the area being planted. The

plants were re-planted, most survived and no further

damage occurred. Finch damage to flower heads is also

an issue where there are shelter belts or hedges nearby.

The birds will perch on the flower stem, cut open the

receptacle and pull out the individual florets. Damage

only occurs to mature flowers at the stage when the petals

have started to whether. This flower development stage

Arnica crown rot, A) Recovery of some infected plants, B) Shoot

wilting symptoms in two year old plants, C&D) Basal rot symptoms.

Finch damage to a mature arnica flower


also corresponds to when the SL concentration in the flower is at its highest.

4 Flower Production

4.1 Time of flowering

The plants can produce some flowers in the autumn of the first season but the main

production would be expected to start in the spring of year two. The onset and rate of

flower development is dependent on the weather. In our experimental trials at

Invermay in a mild spring flowering has started at the end of September, but the first

flowers did not start to appear until the end of October in a cold spring. Currently

available seed lines are all highly variable in its flowering. The Arbo variety was slightly

less variable than seed sourced from the wild. Flowering can extend over more than a

two month period with the period of flowering much long in the first year and slightly

more compressed in subsequent years. In a first year crop, depending on the

environment, less than 50% of plants may flower, but this increases to over 80% in

subsequent years. At the highest and coldest site (Styx Creek) more than 95% of the

Arbo plants flowered in the first year.

4.2 Effect of flower maturity on quality

The timing of the flower harvest is critical to the concentration of the lactones in a flower

head. As shown earlier the lactone concentration progressively increases as the flower

matures from a bud to a pollinated flower with petals withered. The mass of the flower

head increases as the florets are pollinated and the seed starts to fill. The total lactone

content of New Zealand grown Arnica montana between 0.66% and 0.94%, is typical of

the quality found in Europe. Therefore harvesting more mature flowers will produce a

product with a high SL quality. An open flower can remain unpicked for 5-10 days and

the pick and re-pick of the flower crop is dependent on the seasonal growth conditions.

4.3 Flower harvesting and post harvest handling

Because of lack of uniformity of the flower stem architecture and poor synchrony of

flower maturity currently available seed lines are best suited to hand harvesting. The

cost of labour to pick flowers is quite a significant component of the production cost. To

pick only flowers at a set flower development stage is much more time consuming than

picking all flowers that are open at that time. We have found that if the first harvest is

delayed until a large proportion of the terminal flowers have all florets open and petals

withered (our flower development stage H) and this will optimise the quantity of flower

material available. Subsequent harvests can then be undertaken at 7 to 10 day

intervals depending on rate of flower development.

Flowers can be plucked from the flower stem using the thumb and index finger or

sliding a group of flowers between the index finger and the second finger and pulling

upwards in a sharp action. Collecting a quantity of plucked flowers in the palm of the

hand before transferring the flowers to the harvest bin, as opposed to transferring after

each plucking movement also speeds up the rate of picking. The rate of flower picking

is dependent on flower density but an average yield of 2 to 5 kg/hr of fresh flowers is

possible. In high flower densities picking two planted rows at a time, a picker will

harvest the equivalent of 0.8 to 1.0 kg of dried flowers per hour. We have also found,

using cheaply constructed inline two wheeled trolley with pneumatic tyres and an

adjustable seat which is pushed backwards down the lane way between the arnica

beds, also makes picking easier and reduces back strain. Picked flowers can be


dumped into large plastic bins with handles that can be pulled behind the trolley.

Disposable gloves should be warn when picking flowers to avoid skin reactions and

wearing long sleeves or arm guards will minimise brushing contact of the arms and

wrist areas against the flowers and flower stems. Pickers also need to be aware of

bees working the crop and the gloves can provide some protection against a bee string.

A trial simulating mechanical harvesting of arnica flowers has been undertaken arnica

grown from an unselected seed line in New Zealand (Douglas et al 2004). The flower

stems were cut using electric hedge trimmers, the stems were dried and then the

flowers were mechanically separated from the low quality stem material to produce a

product of the same quality as the hand harvested material. The simulated mechanical

harvest treatment yielded over twice the total herbage as the hand-picked treatment,

but 34% of this material was the low quality stem material that was thrown away after

drying. Efficient mechanical harvesting of arnica flowers requires plants with more

uniformity in plant structure, time of flowering and flower development than currently

found in the unselected lines. Crop & food Research have a plant breeding programme

looking to increase the uniformity of these characters plus increase flower yield.

Once harvested the bulk flower material should be quickly dried or stored over night in

a cool room (1-3°C), if drier space is not immediately available. Large quantities of

picked flower material can rapidly heat to over 50°C, within 2-3hr when held at ambient

temperatures in midsummer. We have stored flowers in 40 litre stacker crates to avoid

heating. Heating can also occur in the chiller if the quantity of flower material in a bin or

container is too large or too tightly packed.

There are many types of commercial drying systems available and professional advice

should be obtained to identify the most suitable unit. Ideally the flowers should be dried

in the dark, in a forced air drier, at 40°C-45°C, to less than 10% moisture content and

within 24 hrs. Ideally the unit should have also humidity control. In a batch drying

system we have found galvanised sheet metal trays 70mm deep with a stainless steel

mesh with a small gap between each layer of trays works very well. If the trays are any

deeper than this or if the flowers are packed too tightly into the tray then the centre of

the layer dries very slowly and it may be necessary to remix the trays to get the product

dry. Slow drying can encourage the growth of yeast and moulds. Once dry the

individual florets in the flowers will have puffed up like a dandelion head and the

receptacle and stem will be brittle to the touch. The packing of the trays should be

done as uniformly as possible to ensure even air low throughout the whole drying stack.

An low cost in-line two wheeled adjustable seat trolley for flower harvesting.


It is advised to wear gloves and have the arms covered when packing the fresh flowers

into the trays and in addition when emptying the dried trays a dust mask should also be

warn. The type of storage packing material is normal determined by the buyer. New

packaging rather than recycled materials should be used.

4.4 Flower Yield and returns

Flower yields are still quite variable most first year crops on lowland sites have yielded

between 150 and 300 kg/ha of dried flowers from unselected seed lines and the

German Arbo variety. At the Styx Creek site the average first year dried flower yield for

700kg/ha from the Arbo variety was. Data on flower yields Yield from second year

crops in New Zealand is still limited. Results from bulk plantings have ranged between

570 and 100 kg of dried flowers per ha. From the selected breeding material the flower

yields greater than 700 kg/ha have been obtained in the first year and over 1000 kg/ha

obtained in the second year from some of the better performing material. The current

price for dried arnica flowers is between $60 and $100/kg in New Zealand.

5 Acknowledgements

We thank the MAF sustainable farming fund, Weleda NZ Ltd., Crop & Food Research

and Venture Southland for their financial support of this project. We thank Ruth

Gardener, Pauline Seaton, Nancy and Bob Allen, Rob and Amy Markellie and Craig

Howard for information and images from the SFF arnica trial sites. Thanks to

Rosemary Anderson, Alison Evans and Tom Orchiston for information from the

Invermay trials and to Paul Verdonk for information on organic propagation of arnica in

cell transplant systems.

6 Sources of Information

Bisset, NG, Ed. (1994). Herbal Drugs and Phytopharmaceuticals. A handbook for practice on a scientific basis. Stuttgart, medpharm. pp.83-87.

Douglas JA, Smallfield BM, Burgess EJ, Perry NB, Anderson RE, Douglas MH Glennie, V. A. 2004. Sesquiterpene Lactones in Arnica montana: a Rapid Analytical Method and


the Effects of Flower Maturity and Simulated Mechanical Harvesting on Quality and Yield. Planta Med. 70: 166-170.

Dunlop, E 2003. The story of Dunedin Botanic Garden New Zealands first. Pub. Friends of Dunedin Botanic Gardens Inc. pp.284

Lange, D. (1998). Europe's medicinal and aromatic plants: their use, trade and conservation. Cambridge, TRAFFIC International. pp.73

arnica montana a grower s guide for commercial production...

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