GROWING INCENSE TREES

For several years now I have been building up a collection of Boswellia (frankincense) and Commiphora (myrrh) trees, all of which will have to be content to grow more or less as bonsai. They seem easy to grow in pots, but are leafless during the winter, and during the summer, too, if I don’t water them regularly. In the spring, after their winter dormant period, all of these trees start to leaf out, so at that time I try to give them plenty of water to facilitate the process. One day early last spring I noticed that the Boswellia neglecta had a big drop of resin exuding from a place where it had been trimmed months previously. I can only conclude that when the plants break dormancy their sap starts flowing the way maple sap does, and that it leaks out of any cut area. After producing sap, the little tree put out some nice, green, frond-like leaves, lost them during the winter, and has now grown more leaves. Through all this, the resin drop has kept hanging on. 

Early this spring the little Boswellia carteri tree lost its leaves, at which time some tiny drops of resin oozed out along the leaf stems. I collected these drops and tasted them, which was the best and easiest way to evaluate them. They tasted and smelled exactly like frankincense oil. This is already way more that I had hoped for when I bought the tree as a curiosity.

I also have a 3-foot (1 meter) tall Commiphora tenuipetiolata tree that had started to branch out from the side of the trunk. One of my assistants bumped against it last fall and broke the branch partially off. A week or so later I noticed a blob of resin accumulation around the break. This tree is actually large enough to produce some significant resin, so that made me think that maybe I'll be able to harvest a little incense from my plants after all! There should at least be a few small drops that I can burn. I’m looking forward to having some frankincense, but it will be especially interesting to see what the resin of all of the different Commiphora species smells like. 

[All photos are mine]

FRANKINCENSE

Frankincense, also known as olibanum, is among the most wonderful of all natural perfume materials. I love it on its own, and as the basis of the “incense” note, but it’s also extremely versatile in combining with all kinds of other scents. Frankincense is the resin of a type of shrubby tree belonging to the genus Boswellia, which grows under harsh desert conditions, mainly on the Arabian Peninsula, in North Africa, and in India. The resin is collected by making cuts in the bark of the trees, allowing the sap to leak out and harden, forming frankincense “tears”. For incense, the tears are burned as is, or powdered and mixed with other things. The powdered resin can also be used to make a tincture. The resin is distilled to produce its essential oil.

Frankincense is probably familiar to some as “church incense”, which traditionally was Boswellia sacra or papyrifera, sometimes mixed with other aromatic substances such as myrrh and spices. There are many different species and varieties of Boswellia, all of which smell a little different, but all of which have a deliciously aromatic resiny scent.

How to describe frankincense? It’s like trying to describe the scent of a rose. It is what it is, and once you smell it there’s no mistaking it. Just as nature provides uncountable variations on the rose theme, there are variations on frankincense. I’ve been sampling a number of different types of Boswellia, and thought it would be interesting to write down some observations about each one.

Boswellia carteri: This comes from Somalia and Ethiopia. It’s the prototypical frankincense scent, rich and complex, with citrusy, resiny notes, the typical spicy, fruity, “incense” heart, and a bit of almost animalic woody scent, the funkiness of which goes away after a little while. B carteri is one of my favorite all-purpose frankincense varieties.

Boswellia sacra: The one that I have comes from the Dhofar Valley in Oman, and is similar to carteri, with all of the fruity, woody, incense-y notes, but a bit sharper, with more wood and spice notes. It’s a wonderful oil that I’m saving for something special.

Boswellia freereana: The one that I have is from Somalia, and has much more of a citrusy, pine-needle scent and less of the deep, woody, incense-y base. It’s sort of a “frankincense lite”. The woody note is more cedar-like than the other types.

Boswellia serrata: From India, it’s similar to freereana in that it’s a somewhat lighter scent. It doesn’t have the pine-needle note, but it is citrusy, with a characteristic sweetish woody scent of its own that’s hard to describe, but is very much like “church incense” with a tiny touch of vanilla.

Boswellia neglecta: From Kenya, this is a fairly heavy hitter, in the same league as sacra and carteri, but with slightly less of the funky-woody note. It’s a wonderful incense scent.

Boswellia papyrifera: I could have sworn I had this one, but all I can find is the resin tears, not the oil. My recollection is that it’s similar to sacra and carteri. I’ll search again and update in due course.

One of the interesting things about frankincense essential oil is that it gets better with age. I have a small amount of generic frankincense essential oil that’s at least 15 years old, and it’s the best I’ve ever smelled. I doubt that any of the oils that I currently have will make it that long, but if they do, they will make some amazing perfumes.