Lavender (Lavandula spp.) is widely associated with warm, dry Mediterranean climates, where well-drained soils and long hours of sunshine support robust growth and high yields of essential oils. Scotland being characterised by high precipitation, humidity and cooler average temperatures, suggest that it would be an unlikely location for commercial cultivation of lavender. However, a small-scale lavender farm has emerged in Scotland in the past decade. This raises the question of whether ongoing climate change – and the warmer temperatures it brings – is making Scotland increasingly viable for this crop. In this report, informed by my four years of experience working at Tarhill Farm in Kinross, and a primary interview with the farm’s manager, I argue that while warming temperatures could offer marginal benefits, precipitation and drainage remain the dominant limitations for lavender cultivation in Scotland.

Lavender’s optimal growing conditions are well-established. The plant thrives in full sunshine, low humidity, well-drained and often alkaline or sandy soils. It is highly intolerant to waterlogged conditions, with the excess moisture in the soil posing a risk of root rot, which is one of the most common causes of plant failure in wetter climates. One of the most widely cultivated varieties; Lavandula angustifolia (including the Folgate cultivar, planted at Tarhill), offers a greater tolerance to wet and cold conditions than the hybrid Lavandula x intermedia (Grosso cultivar planted at Tarhill) which highlight variety selection as an important adaptive consideration in marginal climates. Oil content and flowering are closely linked to the accumulated warmth and sunshine hours during the short growing season, suggesting that years with cool, overcast summers may delay the harvest and/or reduce the yield.

Scotland’s climate is changing in ways that are complex and not necessarily favourable for lavender. Mean annual temperatures have risen across Scotland, with the Met Office recording a clear warming trend over recent decades and UKCP18 projections indicating further increases of up to 2-3ºC by the mid-century. The frost-free growing season is increasing, which benefits heat-loving crops like lavender. However along with this comes a shift in precipitation patterns. While eastern and southern areas have seen drier summers, many western and upland areas have seen the consequences of increased rainfall in winter, and more intense storms. These weather changes are concerning for lavender growth as it is not simply the volume of annual rainfall that matters the most, it is the distribution and intensity, particularly during the August harvesting window as the heavy rain can damage the plants and overcomplicate harvesting.

Lavender cultivation at Tarhill Farm was established in 2015 and has expanded in scale since, though it has maintained its focus on two principal varieties: Folgate (L. angustifolia) and Grosso (L. x intermedia). The farm’s experience over the last decade offers useful evidence of how the climate interacts with cultivation decisions that are in practice.

According to Rory Irwin, who has managed the farm since its establishment, drainage has been the central challenge, not the temperature. The farm benefits from the naturally sandy, porous soil, especially at the base of the south and south-west facing slopes, as it provides well-drained ground. Despite this, the raised rows were introduced from 2021 onwards when planting extended to the west brae. This was done by using a plastic membrane to actively divert the rainwater away from the root systems. This decision was actively driven by the concern over the wet conditions as opposed to any temperature-related factor.

When asked what matters more for the lavender’s performance – warmth or rainfall, Rory was unambiguous: “Wet. Lavender can tolerate the warmth and grows well in Mediterranean climates. If it were not for our drainage works, the lavender would not survive here”. They added that a further increase in Scotland’s average temperature would have no adverse effects on the plant, except for ancillary risks such as new diseases moving northward. Increased frequency of heavy rainfall and storms, however, would require a proportionate increase in protective measures.

Flowering dates have remained noticeably consistent, typically around the 28th of June each year. Harvesting dates, however, have varied by up to two weeks and this ranges between early to mid-august across different seasons. The cause of this variation is not fully understood, but it is plausible that cooler or wetter summers delay the point at which the plants reach the highest oil content. This relationship would require further investigation through cross-referencing local meteorological records with lavender harvest logs, which Rory suggested.

The changing climate in Scotland presents a mixed picture for lavender cultivation. Rising temperatures and a longer growing season are generally beneficial for those crops who lie in warmer regions, however the evidence from the farm suggests that temperature has not been the binding constraint. Drainage and rainfall management have been the focused issues. The adaptive practices such as the raised row planting and improved root systems are already doing significant work to make Scottish lavender viable, and these efforts are a response towards the increased precipitation rather than additional warming. If the precipitation in Scotland becomes more frequent, as some projections show, the effort that is required to maintain adequate drainage will increase accordingly. On the other hand, Scotland may be becoming marginally more viable for lavender as temperatures rise, but the crop’s long-term success here appears to depend on less warming, and more effective water management to ensure the roots of the plant stay dry.

• Scottish Government/Scotland's Environment — observed and projected Scottish climate.
• Met Office UKCP18 — temperature and rainfall projections.
• Met Office — heavy rainfall projections.
• RHS — general lavender cultivation/drainage requirements.
• RHS — Folgate cultivar.
• RHS — Grosso / L. × intermedia.
• Hassiotis et al. (2014) — environmental conditions and lavender essential-oil production.