Goldenseal (Hydrastis canadensis)How well established is this crop?
Initial trial plantings of these crops may have been done. There is little information on plant suitability to the region and no current information on markets, commercial returns or current research. This is a new crop.Background
Goldenseal is a highly valued medicinal herb originating in North America. It grows naturally on the forest floor and does not tolerate bright sunlight. Growing under pine plantations in the years before ‘canopy closure’ may be one way to grow the herb in a simulated wild environment. The other way is to grow it under large artificial shade structures in a similar manner to those that growers use for Ginseng.
Goldenseal is also known as yellow root, orange root and Indian dye. In traditional medicine it has a range of uses including a muscle stimulant, stomach strengthener and laxative.
Goldenseal over-winters as a fibrous root mass beneath the soil surface. It does not seem to be affected by the cold. Its parts of its natural environment in North America it is covered by snow for 2-3 months of the year so it should produce successfully in Otago.Rainfall and Irrigation
Rainfall does affect Goldenseal. However, the leaves are very susceptible to fungal disease when wet. In North America growers spray fungicides almost as soon as it has stopped raining.
If irrigation is needed a drip system on the soil surface is thought to be the best. Regular watering will result in a greater root mass than un-watered plants.
Goldenseal needs to grow in the shade and in most situations where this occurs, shelter from the wind is also provided.Soil
The key physical requirement of the soil for Goldenseal growing is a free draining root zone with a high sand content. This ensures that when you dig the plant from the soil, the whole root mass comes away and can be processed.
Goldenseal grows naturally on a forest floor which has a pH of around 5-6 and not a lot of excess fertility. It is a small, slow growing plant. Be very careful to not over fertilise as the plants can die.Weed Control
You will be growing Goldenseal in relatively low light conditions. This tends to mean low weed pressure as they do not like growing in these conditions. If weeds do become an issue hand hoeing or pulling is the best way to control them. It is advisable to have perennial weeds such as thistles under control before planting as these will grow in the low light conditions.Varieties
There is only one variety of goldenseal.Pests and Diseases
Goldenseal seems relatively free of pests and diseases. Growing the plants in a free draining soil is the key as this prevents root rots. Foliar diseases do not appear to be a problem. Insect pests do not appear to be an issue, but watch for both grass grub and porina at the times of year when these insects are pests in other crop.
Rabbits are the only vertebrate pest of Goldenseal. Although they have not been seen to actually eat the plant, they do dig around the roots affecting yields.
Plant spacing depends on the regime they are being grown in. Traditional spacing is about 20cm between plants. Allowing for access rows the beds should be around 1.5m wide at a maximum.
Goldenseal is planted as small root pieces and needs to grow for at least 3 seasons before the roots grow to a suitable size for harvest. During this time they need to be watched regularly for things such as weeds and pest damage. They die down every autumn and the plant over-winters as a root mass and bud before coming away again in the spring. Removing the dead foliage in the winter will reduce any incidence of disease carrying over from one season to the next.
Roots are harvested using a modified potato digger, dragged through the beds or by hand digging. After being exposed people with baskets pick up the roots sitting on the soil surface. They are then washed and dried down to a moisture content of between 8-10%. Once this is done the crop is ready for sale or for further processing into pills, crushed root etc.Equipment
Many growers start with a rake, some small plants and a cover structure or they grow under trees. Larger growers may be best to start with more elaborate equipment such as tractors, rotary hoes, beds formers, spray rigs, straw spreaders for mulches etc.Returns
Returns at market for New Zealand grown goldenseal is unknown because none has been grown for sale at this time. Processing the raw roots into some sort of final product will be the best way to ensure that maximum dollars are returned back to the grower.
The latest information from America shows Goldseal trading at around NZ $70/kg for dried root.
If you are thinking of growing Goldenseal contact Crops and Food Research for their latest information. www.crop.cri.nz
The New Zealand Tree Grower magazine also has a good article on Goldenseal in the November 2004 issue.