The genus Commiphora Jacq. contains the myrrh trees. This Burseraceae genus, described in 1797 (conserved name), brings together about 190 species of trees and shrubs from the dry tropical regions of Africa, Madagascar, the Arabian Peninsula, the Indian subcontinent and South America. Many have a swollen trunk or caudex, peeling bark and deciduous foliage, which makes them sought-after collection plants. Their cultivation is nevertheless poorly documented: most of the information comes from nurseries and from a few studies on two or three species. This article gathers what the sources allow us to state about container culture, outdoor planting, propagation and conservation, and flags clearly what remains uncertain.
At a glance
- Climate: dry tropical genus, frost-tender; in temperate climates, pot culture with a frost-free winter is the rule.
- Substrate: very free-draining and mineral (sand, pumice).
- Watering: moderate in the warm season, let the mix dry out completely between waterings, stop in winter for species that go dormant.
- Propagation: by seed (sorted) or cuttings; large cuttings root easily in some South African species.
- In the ground: only in frost-free regions; no documented results found for temperate Europe.
- Conservation: Commiphora wightii is Critically Endangered; buy only nursery-propagated plants.
Which species will you meet?
Here are some species mentioned in the sources or offered in collections:
- Commiphora myrrha (T.Nees) Engl.: true myrrh, native from eastern and south-eastern Ethiopia to north-eastern Kenya and the south-western and southern Arabian Peninsula, in desert or dry shrubland.
- Commiphora wightii (Arn.) Bhandari: the guggul of India and Pakistan, a slow-growing spiny shrub tapped for its gum-resin and now threatened.
- Commiphora kataf (Forssk.) Engl.: a small tree of the Horn of Africa and Arabia, up to 8 m in the wild. An LLIFLE entry says it needs a sunny position and a well-drained soil, and tolerates pruning.
- Commiphora humbertii: a caudiciform species from Madagascar, described as slow and compact, about 40 cm tall at maturity.
- Commiphora harveyi (Engl.) Engl. and Commiphora woodii Engl.: two South African trees documented by PlantZAfrica; the latter grows fast.
- Commiphora unilobata: naturally short, with a thick caudex, widely spaced branches and orange-yellow peeling bark; from Kenya, Somalia and Ethiopia, uncommon in cultivation.
- Commiphora planifrons: a Socotran species whose propagation has been described in the Cactus and Succulent Journal.
Names and taxonomy
The name Commiphora comes from the Greek and refers to the gum the tree bears. DNA analyses show the genus is monophyletic, but its traditional sections do not reflect real relationships. Gostel, Phillipson and Weeks (2016) proposed seven infrageneric clades and showed that Madagascar holds 44 endemic species, nearly a quarter of the genus. Only one species, Commiphora leptophloeos (Mart.) J.B.Gillett, occurs in the Americas. The sister genus is Bursera. Plants of the World Online (Kew), the nomenclatural reference on this site, accepts the genus across a range from Africa to Sri Lanka and several South American countries.
In the wild: understanding the needs
Commiphora live in seasonally dry tropical forests, dry shrubland and desert zones. They tolerate heat and drought, store water in the trunk or roots (people chew the soft heartwood of Commiphora harveyi to rehydrate) and drop their leaves when water is short. The resting rhythm varies with the species and its origin: some caudiciforms sleep in summer, others in winter. Observe each plant before fixing a watering calendar.
Container cultivation
Light and temperature
Most species want strong light: full sun for Commiphora humbertii according to its seller, bright partial shade for Commiphora kataf according to another. Move plants outdoors in summer to a warm spot, acclimatising them gradually to the sun. One commercial sheet gives Commiphora kataf a maximum of 35 °C and a minimum of 5 °C; treat this as an order of magnitude.
Substrate and pot
Drainage comes first. Use a mineral mix: one sheet advises lightening potting soil with sand or pumice. The pot must have drainage holes and be sized to the roots; an oversized pot keeps water too long.
Watering
Water only when the substrate is completely dry. An Italian nursery gives for Commiphora brevicalyx weekly watering in spring and summer, reduced every two months in autumn, then suspended in winter. This is a useful example but specific to one species and set of conditions. Overwatering is the commonest mistake: one seller notes that Commiphora kataf tolerates a constantly moist soil very badly.
Feeding and pruning
I found no genus-specific fertiliser recommendation. In practice, as for most caudiciforms, a diluted feed during growth is enough, stopped during dormancy. Commiphora kataf can be pruned without difficulty to keep it compact.
Overwintering
Bring plants in before cold nights, to a bright, frost-free place. For species that drop their leaves, rest means little or no watering. A sheet for Commiphora humbertii gives USDA zones 10 and 11 in its table (9 to 11 in the text), and a sheet for an unidentified Commiphora (Plant Lust) gives zones 9a to 11: in every case frost is not tolerated.
Outdoor and in-ground cultivation
Planting in the ground is only realistic in frost-free climates. PlantZAfrica states that Commiphora harveyi can be grown in most of South Africa except frosty areas, as it is frost-sensitive. Commiphora wightii is grown commercially in India and Pakistan, in arid or semi-arid climates, with the only notable disease being collar rot in the rainy season. Plant in full sun in a stony soil, on a mound or bank, away from any hollow. In a Mediterranean-type climate the main risk is winter wetness more than cold alone; this is horticultural reasoning, not a documented result.
Hardiness: what the sources say
None of the sources consulted documents multi-winter results in the ground in temperate Europe. The available benchmarks are indicative: USDA zones 9a to 11 for a Commiphora offered by a US nursery, 10 to 11 for Commiphora humbertii, and confirmed frost sensitivity for Commiphora harveyi. Any field observations you have would be valuable for completing this section.
Propagation
Seed
The figures mostly concern Commiphora wightii. Only black seeds are viable; white, immature seeds do not germinate. One Indian sheet mentions about 40% germination, while another, which sorts seeds by flotation (the white ones float), reports 70 to 90% for black seeds, against 1 to 4% under natural conditions. One seed can produce several seedlings (polyembryony).
Cuttings
Results vary widely. For Commiphora wightii, an Indian sheet reports about 90% rooting of leafless stem cuttings taken in May, whereas a 2000 study (Mertia and Nagarajan) obtained 10% with hardwood and 40% with tender cuttings. For Commiphora harveyi and Commiphora woodii, PlantZAfrica describes large cuttings (truncheons) rooted in sand in a warm, humid place, in three to four weeks for the former. For Commiphora planifrons, 15 cm semi-hardwood cuttings were rooted with hormone, bottom heat and mist in a propagation house.
Pests and diseases
Collar and root rot caused by excess water dominates. In Commiphora wightii, collar rot in the rainy season is attributed to the fungus Sclerotium rolfsii; no other serious disease is reported. In collections, watch for mealybugs and spider mites, as with most caudiciforms: this is general horticultural advice, not an observation specific to the genus.
Conservation, regulation and toxicity
Commiphora wightii is rated Critically Endangered by the IUCN (Ved et al., 2015), because of over-harvesting for guggul and very weak natural regeneration. Commiphora guidottii Chiov. ex Guid., the scented myrrh of Somalia and Ethiopia, is rated Vulnerable, threatened by charcoal production, excessive resin extraction and climate change. Before importing seed or plants, check the regulations (I have not verified whether any species are CITES-listed) and buy only nursery-propagated plants. I found no reliable toxicity data: as a precaution, do not ingest the plant or its resin.
FAQ
Can a Commiphora be grown indoors?
Yes, some species are sold as houseplants, provided there is a very bright window, a free-draining substrate and measured watering.
My Commiphora is losing its leaves: is that serious?
Often not, it is a rest period. If the substrate is damp and the caudex is soft, suspect rot instead.
Can you harvest myrrh from a cultivated plant?
Not in usable quantities. Commercial myrrh comes from trees tapped in their native habitat.
Which species should a beginner choose?
I found no rigorous comparison. Commiphora kataf is presented by one seller as easy and tolerant of pruning; that is only a commercial opinion.
Reference websites
Plants of the World Online (Kew), Commiphora genus page: reference nomenclature and distribution, reliable. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:331509-2
Plants of the World Online (Kew), Commiphora myrrha: range and biome. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:127741-1
Plants of the World Online (Kew), Commiphora wightii: IUCN Critically Endangered status. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:127856-1
PlantZAfrica (SANBI), Commiphora harveyi: frost sensitivity and cuttings; South African institutional source. https://pza.sanbi.org/node/11849
PlantZAfrica (SANBI), Commiphora woodii: fast growth and cuttings. https://pza.sanbi.org/node/12455
LLIFLE, Commiphora kataf entry: exposure, soil and pruning; collaborative encyclopedia, to be cross-checked. https://llifle.com/Encyclopedia/TREES/Family/Burseraceae/33337/Amyris_kataf
LLIFLE, Commiphora guidottii entry: distribution and status; collaborative encyclopedia. https://llifle.com/Encyclopedia/TREES/Family/Burseraceae/33350/Commiphora_guidottii
Giromagi, nursery (Tuscany, Italy), Commiphora brevicalyx: watering calendar; commercial source. https://www.giromagi.com/en/shop-caudex/commiphora-brevicalyx
Planet Desert, Commiphora humbertii entry: habit, hardiness zones; commercial source. https://planetdesert.com/products/commiphora-humbertii
Araflora, Commiphora kataf entry: indicative temperatures and moisture sensitivity; commercial source. https://www.araflora.com/product/commiphora-kataf-s/
Plant Lust, Commiphora sp. entry: planting zones, nursery-supplied data. https://plantlust.com/plants/46063/commiphora-sp-mdoro
Canarius, Commiphora unilobata entry: species description; commercial source. https://canarius.com/it/piante/succulente/commiphora-unilobata.html
Vikaspedia, Commiphora wightii: Indian growing protocol (seed, cuttings, diseases). https://en.vikaspedia.in/agriculture/crop-production/package-of-practices/medicinal-and-aromatic-plants/commiphora-wightii
ICFRE (India), technology sheet on guggul germination: selecting viable seeds. https://afri.icfre.org/pdf/UserFiles/File/technology/t_12_load.pdf
Bibliography
Gostel, M.R., Phillipson, P.B. & Weeks, A. (2016). Phylogenetic reconstruction of the myrrh genus, Commiphora (Burseraceae), reveals multiple radiations in Madagascar and clarifies infrageneric relationships. Systematic Botany 41(1). doi:10.1600/036364416X690598. [Seven infrageneric clades, 44 endemic species in Madagascar.]
Gostel, M.R. (2015). Systematics and evolution of Commiphora Jacq. (Burseraceae) in Madagascar. PhD dissertation, George Mason University. [Describes the genus: nearly 200 species, range.]
Ved, D., Saha, D., Ravikumar, K. & Haridasan, K. (2015). Commiphora wightii. The IUCN Red List of Threatened Species 2015: e.T31231A50131117. [Critically Endangered assessment.]
Mertia, R.S. & Nagarajan, M. (2000). Successful rooting in cuttings of Commiphora wightii (Arnott) Bhandari. Annals of Arid Zone 39(1): 87-88. [Rooting rates of 10% (hardwood) and 40% (tender cuttings).]
Propagating Commiphora planifrons: an exercise in patience and experimentation. Cactus and Succulent Journal 83(5). doi:10.2985/0007-9367-83.5.216. [Cuttings and seed production in a humid greenhouse; authors not noted.]
Nayak, S.L., Suthar, M.K., Sarkar, R., Khadke, G., Mittal, M.K. & Das, M. Guggul (Commiphora wightii [Arn.] Bhandari): from sacred resin to endangered resource: a review. doi:10.1017/s1479262126100793. [Review of the decline and conservation of guggul; I read the abstract only.]