It is over three months since we had rainfall here in Northern Arizona. At this time last year, we had experienced both winter rain, freezing temperatures, and even our first snowfall of the winter. This year it is a different story. So how does this lack of moisture affect both the winter plants and the potential development for spring plants, specifically with regard to aromatic plants? Here is a quick look.
The Aroma of Winter in the Landscape
In the northern hemisphere, we associate winter with the aromas of evergreens, firs, and tree aromas – probably because these plants are not dormant and their oils are one of the few aromas we pick up from the landscape. Tree aromas vary, but can be calming, cleansing, or stimulating, depending upon the tree species.
Snow and ice traditionally cover many northern winter landscapes, but a lot of plants survive these harsh winter conditions and produce new growth in the spring. Winter is the hardest season for a plant’s survival; plants need water to live and in winter the soil is often frozen with ice and snow, trapping any water within it. The plant can not replace any water losses and as a result, the plant will die. Plants and trees have adapted various ways in which to survive the traditional winter.
What Happens to Aromatic Plants in Winter?
Aromatic annual plants do not the survive winter and flower for only one growing season. New seeds have to be planted in the spring to produce the next year’s growth and harvest. Aromatic annual species include sunflower (Helanthius annuus), German chamomile (Matricaria recutica) and basil (Ocimum basilicum). Perennial plants do survive the winter but “hibernate” under ground. The growth above ground dies at the end of the growing season but the roots of the plant are protected by snow, which acts as insulation; new growth traditionally follows in the spring. Aromatic perennial plants include sage (Salvia officinalis), oregano (Origanum vulgare) and rosemary (Rosmarinus officinalis).
Deciduous trees effectively become dormant throughout the winter months as well. They drop their leaves in the Fall and as a result do not need to photosynthesize and need little water. The tree has received enough nutrients through photosynthesis in the spring and summer months to maintain it throughout the winter, once its leaves have fallen.
Evergreen plants or coniferous trees, such as pine (Pinus sylvestris), fir (Abies balsamea), and Douglas fir(Pseudotsuga menziesii), do not lose their leaves in winter. Cypress (Cupressus sempervirens) and juniper (Juniperus communis) also fall into this category.
The needles of evergreen trees hold little water; the needles primarily contain sugars, alkaloids and non-freezing essential oils (which is why we smell their aromas during this time). The needles of the evergreen tree evolved from leaves to minimize water loss and ensure the tree’s survival throughout the winter. Evergreens are slow to photosynthesize and can maintain functions in lower temperatures than other plants.
How Snow and Winter Rain Help Aromatic Plants to Survive Winter
Snow and winter rain is vital to the winter survival of plants and trees. Snow acts as an insulator and protects the plant from harsh, winter conditions. Snow flakes have a unique structure; they have small intervening spaces within their structure which are filled with air. This means there is low heat conductivity; as a result, the daily temperature penetration into the snow is minimal and plants are protected from frost and freezing conditions. Once the snow melts, the moisture is also good for the plants.
The Effect of Changing Weather Patterns on Plants
In some areas of the world snowfall is reducing; in other areas of the world snowfall is occurring earlier in the season than it has traditionally occurred. A 2007 UNEP report Global Outlook for Snow and Ice stated that in the northern hemisphere snowfall had reduced by seven to ten per cent over the last forty years for the months of March and April. Throughout the northern hemisphere, the period of the year when there is no snow cover has also lengthened.
If snowfalls occur early in the winter season, or even at the end of Fall, some plants may traditionally be unprepared for the sudden climate change which may result in the plant dying; however, should snowfall be later or lighter in the traditional winter months, plants may struggle to survive too.
The Future for Aromatic Plants
Each time we reach to use a bottle of essential oil or another aromatic substance, we are using a precious and valuable resource. If weather patterns continue to change, plants may become stressed, confused, and struggle to survive. It is for this reason, we are developing the Sedona Aromatics garden, in order to study aromatic plants further, distill our own oils and waters, and learn how we can adapt to help certain aromatic species survive changing weather patterns.
The Study of Aromatic Plants in Aromatherapy
To learn more about how aromatic plants are used in aromatherapy practice, consider the Sedona Aromatherapie Linguistics of AromaticsTM program!
Global Outlook for Snow and Ice, accessed from: http://onlinelibrary.wiley.com/doi/10.1111/j.1751-8369.2008.00046.x/full (Original report no longer available online)
The author of this article has a 20 year history in the health care and aromatherapy industry. She is UK-certified aromatherapist and a NAHA Certified Professional Aromatherapist (R). She is both a published author and editor in aromatherapy, a consultant, custom blend formulator and herbal studies student. She is the author of Authentic Aromatherapy and the current chief editor of the NAHA Aromatherapy Journal. She has taken the online Master Gardener short course series with the University of Oregon. Sharon works from her garden studio in Sedona, Arizona, where she is in the process of creating her own aromatic stillroom on her one acre homestead and aromatic gardens.