Lavender (Lavandula angustifolia)How well established is this crop?
This crop has been grown commercially in the region for over 10 years. Commercial returns, current growers and some level of regional based research is available to help those new to this industry.Background
Lavenders are a well known crop that can be grown for a number of purposes including ornamental garden plants, flower production and essential oils. It is the oil species that will be discussed in this datasheet.
World production of oil comes from a mix of three species.
1. Lavendula angustifolia the narrow leaved lavender. Commonly known as English lavender
2. Lavendula latifolia the broad leaved lavender. Commonly known as Spike lavender
3. Lavendula intermedia a cross between L. angustifolia and L. latifolia. These selections are commonly known as lavandins.
In general, lavandins selections produce the most essential oil per kg of dry matter and account for about 80% of the oil produced worldwide. The rest tends to come from English lavender with only a small amount from the spike lavenders.
All lavender species originate in the Mediterranean areas of Europe; however with plant breeding varieties have been developed that will grow in nearly every climate.Winter Chilling and Frosts
Lavender does not need winter chilling to produce flowering stems.
Late spring frosts can affect this crop by killing the new seasons growing tips. It is on these that the flowers develop. However commercial plantings of lavenders have been made successfully in a wide range of locations throughout Central and Coastal Otago.
Water is essential during the establishment phase of a lavender block. It is also necessary when the crop is developing its flower heads in the period leading up to harvest. If the crop does not get irrigation or natural rainfall over this time the oil yields can be significantly reduced.
Even though lavender is a low growing plant, shelter from the wind is advisable. It will reduce the amount of damage to the plants and subsequent disease problems. Be careful with design to allow the plants to get the maximum amount of sunshine during the growing season.
The key physical requirement of the soil for lavender growing is a free draining root zone. Without this root rots may become a problem.Fertility
Lavenders do not need high levels of soil fertility to grow well. Targeted applications based on soil and foliage tests are recommended. Aim for a soil pH of between 6 and 8.Weed Control
Weed control is essential to maintain the purity of any oil extracted at the end of the growing season. Many growers use weedmat to reduce the amount of herbicides and hand weeding needed during the season.Varieties
There are a huge range of lavender varieties. Talk to local growers with similar climates before deciding on which species to pursue. Trial plantings are recommended, to further decide which varieties suit the property.
Lavenders suffer from few insect pests. Watch for spittle bug as the summer progresses. These only have one generation per year in Otago, so control once a season is all that is required.
Lavenders do suffer from some fungal diseases, most notably root rots. Growing on the correct type of soil will reduce this.
Rows tend to be planted around 1m apart to allow for machinery access between them. Within the rows plants are spaced at around 50cm apart. Rows can be as long as is practical.General Management
Once the ideal variety for the property has been selected growing lavender is relatively straightforward. Plants are produced using semi-hardwood cuttings taken in either autumn or spring. Young plants should be placed in the field after the last spring frost. Irrigation and weed control are the two most important tasks as the crop develops.Harvest
Most modern lavender plantings are machine harvested. The plant material is ready for harvesting when approximately 80% of the individual florets have open and some are starting to senesce. The oil content in the plant is the highest at this stage.
The heads are then steam distilled to extract the oil. Not many growers have their own distillation unit. Cooperatives or paying a larger grower to process the plant material is more common.
After preparing the ground and planting most work on a lavender block is done mechanically. This means requirements for a tractor, spray unit, harvest machinery, bins etc.Returns
Lavender has been grown successfully in a number of locations, from Central Otago through to the Taieri Plains. Yields vary depending on location and variety. English lavender has been known to produce oil at about 1-1.5ml of oil per kg of fresh flower (around 25L/ha) and lavendins have been known to produce oil at 10-25ml/kg of fresh flower heads (around 140L/ha).
Because lavender oil is an internationally traded commodity, prices fluctuate for a range of reasons. Bottling it yourself and finding niche markets for the final product will maximise returns to the grower.
The New Zealand Lavender Growers’ Association Incorporated