Harvesting Herbs: Dancing With Weather

OK, I'm back! I haven't posted anything since I returned from my back-to-back trips to Mexico and Lake Superior - and, yes, my leg is doing great! I'll provide more on that in a future post.

Unlike last year, during which the warm weather came very early in the spring and the spring and first half of summer were extremely hot and dry, so far this year it has been unusually cool and wet in the region where I live. This can have a significant influence on many plant species. Each plant has an ideal habitat that it prefers, including type of soil, moisture level, amount of sun, and climatic conditions. However, there will be a range of conditions in which it can do well and a wider range of conditions that it can tolerate. What these conditions are and how much variation it can tolerate will vary from plant to plant.

The plant life in my area can be pretty lush when there is lots of moisture like there is this year.

There is always a certain amount of climatic variation in any given region. The amount of variation in the Great Lakes region where I live is probably moderate compared to other regions. However, since around 1970 our climate has been noticeably changing - and the amount of change has been increasing with each successive decade. The kind of change is consistent with what we can expect given global trends: a progressive warming with greater extremes. This has had a noticeable impact on plant and animal species.

So, let's get back to the conditions this year. It is fortunate that, although it has been cooler and wetter, we have at least had one or two sunny days most weeks and even on some of the days that it has rained there have been sunny breaks at some point during the day. As a result, some plants that do very poorly if there has been very little sun are managing to stay relatively healthy.

Many plants that don't do well if there is too much rain and too little sunshine are still doing fairly well this year.

On the other hand, there are a few plants that are looking a bit stressed. This is particularly the case for plants, such as a few of the bedstraw (Galium) species, that grow in lower light areas that are relatively moist. Examples include cleavers (G. aparine) and rough bedstraw (G. asprellum). When there is as much rain as we have been getting this year, the typically moist areas where some of these species grow tend to be moist to the point where they are somewhat wet - and not all plants that grow in these areas necessarily like wet conditions.

Rough bedstraw (Galium asprellum) is finding many of the areas where it lives too wet this year.

As an herbalist that wild-harvests almost all of the medicines that I work with, years when it is very cloudy, rainy and cool can be challenging in a couple of ways. Firstly, most herbs need to be harvested on a sunny day and there needs to be at least one additional sunny day between the day they are harvested and the last rain. For some plants there needs to be two sunny days in between. This is because the plant tissues tend to otherwise be too wet and there are many important constituents, such the components of essential oils, that are produced in much lower quantities if there isn't much sunshine. If there are too few consistent periods of sufficient sunshine, there are also a lot fewer days when herbs can be harvested. If the timing of the sunnier periods doesn't line up with when the herbs are ready to be harvested, I may not get some herbs that year. Secondly, there are some plants, such as red clover (Trifolium pratense) and common St. Johnswort (Hypericum perforatum) that are significantly less potent during such conditions to the point where it isn't even worth harvesting them. In unusually wet (and dry!) years many plants will also be affected by mildew, making them unusable.

Red clover (Trifolium pratense) isn't happy when it's too cloudy and wet!

When the conditions are cooler, cloudier and/or wetter than usual, it is best to harvest herbs in the sunnier parts of their range where they will get maximum direct sun and the soil will be a little bit drier. In years when it is hotter, sunnier and/or drier than usual, it is best to harvest herbs in the shadier parts of their range where they are more protected from excessive sunshine and the soil will be more moist. This year, herbs such as stinging nettle (Urtica dioica), which can tolerate full sun but doesn't usually do well in it, is doing very well in more open areas.

Our native stinging nettle (Urtica dioica ssp. gracilis) is doing very well this year in more open areas.

I typically spend about one day per week harvesting the medicines from mid April to mid May; two days per week from mid May to mid June; three days per week from mid June to the end of July; two days per week in August; one day per week in September; I only harvest on two to three days in October; and then it's back up to two days per week in November. This means that during harvesting season I have to minimize the amount of days that I have a fixed schedule, such as clinic days and scheduled classes and workshops. Which days I need to harvest on depends on when the herbs reach the right stage in their life cycle for harvesting and, of course, the weather! During the peak harvesting season I do my best to allow four to five days per week when I have nothing in particular scheduled so that I can head out on a moments notice whenever the herbs and the weather align! Fortunately, a lot of the work that I do can be scheduled around my harvesting days.

This intensive harvesting schedule means that if I harvest almost all of the herbs I use and don't cut any corners to ensure that the medicines are harvested in a respectful and ecologically sustainable way, and are the highest quality possible, I can only harvest and prepare enough medicines to comfortably run clinics two days per week scheduling about five to seven clients per day. I could maybe do three days per week if I really push it, but I would rather not. These constraints are fine with me. Healing work is very intensive. If one gives oneself fully to the medicine it is very difficult to be completely present when seeing more than 15-20 clients per week. It is essential that any healer live a balanced life and look after their own health and well-being in order to be able to fully live the medicine and offer the most to those who need it.

In my practice I only run clinics one day per week. The rest of the time I do other related work such as teaching, writing, and dealing with the various responsibilities I have as a result of being on the board of directors of both our provincial and national herbalist associations. For almost two years a lot of my time has also been devoted to converting the content of courses to an online format. This will continue for a couple of years, but out of necessity it slows down during harvesting season. By nature I do best with diversity and flexibility. My work also requires that I spend regular time deepening my relationship with Nature and the medicines, whether I'm out there observing or just being.

In years where the weather conditions verge towards the extremes it can make harvesting difficult. For instance, of the sixteen herbs that I had intended to harvest this spring, I only managed to harvest ten of them. Fortunately, I didn't need as many herbs as usual. This is partly because I will often harvest enough to prepare a two year supply of tincture for herbs that I use in low to moderate quantities so that I don't have to harvest every herb that I use every year. For herbs that I use in larger quantities this isn't possible. Also, last year I used less of some of the spring herbs than usual.

 American black elder (Sambucus nigra ssp. canadensis) is right on schedule this year!

Another challenge associated with more extreme weather conditions is that it can significantly alter the life cycle of a plant. Although the timing of some species such as black elder (Sambucus nigra) and yarrow (Achillea millefolium) is pretty consistent from year to year, others can vary by as much as one to four weeks depending on the weather.

This year lance-leaved heal-all (Prunella vulgaris ssp. lanceolata) came into flower sixteen days later than last year.

Ultimately, all I can do is surrender! Herbalists have always had to learn to work with whatever Nature provides. Fortunately, I work with enough medicines that if I can't harvest a sufficient quantity (or any!) of a particular herb in any given year I usually have one or more herbs that are similar enough that I can use as a substitute. In the mean time, looking ahead at the coming weeks there is still lots of rain in the forecast. In terms of the rest of the harvesting season, I'll just have to wait and see how the summer is going to unfold. All I know for sure is it will be an adventure!