Boswellia

Basic Information

Common Name: Boswellia
Scientific Name: Boswellia
Native Habitat: Arabian Peninsula, Northeast Africa (including countries like Oman, Yemen, Somalia, Ethiopia, Eritrea, and Sudan), and parts of India. They typically inhabit dry, rocky, mountainous, or semi-desert regions.

History / Discovery / Cultivator

The genus *Boswellia* is most famously known as the source of frankincense, one of the most ancient and valuable commodities in human history. Its “discovery” wasn’t a singular event by a European botanist, but rather the recognition and utilization of the fragrant resin by indigenous peoples living in the arid regions where these trees naturally grew, dating back thousands of years. Evidence suggests its use in ancient Egypt as early as the 15th century BC, where it was burned as incense during religious ceremonies, used in cosmetics, and incorporated into mummification rituals. The Babylonians, Assyrians, Persians, Greeks, and Romans also highly valued frankincense for religious sacrifices, perfumery, and medicine.

The trade of frankincense was central to the economies of ancient civilizations in the Arabian Peninsula and Northeast Africa. Elaborate trade routes, often referred to collectively as the “Incense Route,” facilitated the transport of frankincense and myrrh from production areas like modern-day Oman (specifically the Dhofar region, famous for *Boswellia sacra*) and Yemen across deserts to Mediterranean ports and beyond. Cities along these routes, such as Petra in modern Jordan, flourished due to this lucrative trade. Control over frankincense production and trade routes was a source of immense wealth and power.

While the resin has been harvested for millennia, the botanical classification and scientific study of the *Boswellia* genus began much later. Linnaeus first described *Boswellia serrata* in 1794. Subsequent botanical expeditions identified and classified other species across its range. The taxonomy can be complex, with numerous species and varieties recognized today, including *B. sacra* (often considered the primary source of high-quality frankincense from the Arabian Peninsula), *B. carterii* and *B. frereana* from Somalia, and *B. papyrifera* from Northeast Africa.

Cultivation of *Boswellia* species has historically been limited and challenging compared to wild harvesting. The trees prefer harsh, rocky, and dry conditions that are difficult to replicate in typical agricultural settings. Most frankincense resin still comes from wild or semi-cultivated trees in their native habitats, often managed by local communities using traditional tapping methods passed down through generations. While there are increasing efforts to cultivate *Boswellia* for sustainable production, large-scale plantations are not common, and the majority of the world’s frankincense supply still relies on the health and accessibility of wild populations. The historical focus has always been on the valuable resin, not typically on the plant as a cultivated specimen in the way many other popular plants are grown, although some species are now appreciated by succulent and caudiciform plant enthusiasts.

Plant Care Summary

Botanical Insights

Adaptations

Boswellia species exhibit remarkable adaptations that allow them to thrive in harsh, arid environments. A defining characteristic is their ability to produce valuable resin, which is exuded when the bark is cut. This resin serves multiple purposes, potentially acting as a defense mechanism against herbivores and pathogens, and helping to seal wounds. The trees often possess thick, peeling, or papery bark, which can help insulate the trunk from intense heat and reduce water loss. Their root systems are adapted to their rocky habitats, either with deep taproots to access water sources or widespread, shallow roots to capture infrequent rainfall quickly. The trunks of many species can become pachycaul (swollen), serving as a water storage reservoir, similar to succulents or caudiciform plants. This water storage capacity, combined with a low water requirement, makes them highly resilient to drought.

Propagation Methods

Propagating *Boswellia* can be challenging and often slow. The most common methods include propagation by seed and by cuttings, particularly large branch cuttings (truncheons). Seeds offer genetic diversity but can have variable viability and require specific germination conditions, often involving warmth and humidity before being transferred to a well-draining medium. Germination can be erratic. Propagation by cuttings is often preferred for specific desirable traits. Large, semi-hardwood cuttings or truncheons taken from mature trees are commonly used. These need to be allowed to callus (dry and heal over) for several weeks before being placed in a very well-draining, sandy or rocky substrate. Rooting can take many months, and success rates are not always high. Providing bottom heat can sometimes encourage rooting. Air layering is occasionally attempted but is less common.

Toxicology

Information specifically regarding the toxicity of *Boswellia* plant *material* (leaves, bark, wood) upon ingestion is limited compared to the extensive research on the medicinal properties and safety of frankincense *resin* and essential oil. Frankincense resin has a long history of use in traditional medicine and as a dietary supplement, and is generally considered safe for ingestion in small amounts according to relevant regulatory bodies when sourced from reputable suppliers. However, the plant parts are not typically consumed. As with many plants not intended for consumption, ingesting *Boswellia* plant material may potentially cause mild gastrointestinal upset in humans and common pets like cats and dogs, resulting in symptoms like vomiting, diarrhea, or lethargy. The resin itself, if chewed or ingested in large quantities, might also cause digestive irritation. Contact with the resin or essential oil can sometimes cause skin irritation or allergic reactions in sensitive individuals. Overall, the plant is not classified among highly toxic species, but caution should be exercised to prevent ingestion by pets or young children.

Common Problems

Pests:

• Spider mites (especially in dry indoor environments)
• Scale insects
• Mealybugs

Diseases:

• Root rot (primary issue, caused by overwatering)
• Fungal leaf spots (less common, typically due to excessive humidity or poor air circulation)

Other:

• Leaf drop (often caused by environmental stress, including changes in light, temperature, or watering schedule, particularly overwatering)
• Slow growth (normal for this genus, but can be a concern for impatient growers)
• Difficulty establishing (cuttings failing to root, seeds not germinating)

Rarity & Value

Rarity:

While the *Boswellia* genus is not inherently globally rare, specific species or well-established specimens can be considered rare for several reasons. Habitat degradation and over-tapping for resin are significant threats to wild populations of several key species, such as *B. sacra* and *B. papyrifera*, leading to concerns about their long-term sustainability in the wild. Cultivated plants are much less common than wild ones, as the trees are slow-growing and propagation can be challenging. Large, mature specimens are particularly rare outside of their native habitats due to the time required for them to grow. Certain growth forms desired by collectors (e.g., substantial caudex development, specific branching structures) also contribute to the rarity of individual plants.

Value:

The value of a *Boswellia* plant specimen is influenced by several factors. The primary determinant is often the *species* itself, with species producing highly prized resin (like *B. sacra*) potentially holding higher value, even as a plant. Size and age are significant factors; larger, older, and more established trees or plants with well-developed pachycaul trunks are considerably more valuable than young seedlings or unrooted cuttings due to the slow growth rate. Provenance can also play a role for collectors. Unlike some other popular plants, variegation is not a typical factor for *Boswellia* value. For enthusiasts of caudiciforms or bonsai, the shape, health, and aesthetic form of the trunk and branches heavily influence the price. Difficulty in cultivation and successful establishment outside native regions also contributes to the value of a thriving specimen.