Ugni molinae

Chilean guava (Ugni molinae)
Scientific name	Ugni molinae
Common names	Chilean guava, murta, murtilla, strawberry myrtle, murtillo, murta-do-chile, goyavier du Chili
Genus	Ugni
Family	Myrtaceae
Order	Myrtales
Native range	Central and southern Chile to southwestern Argentina; cultivated or naturalized in Great Britain, the Juan Fernández Islands and New Zealand
Habit	Evergreen bushy shrub, typically 1–1.5 m in 5–10 years in cultivation; low and compact on dry, exposed sites and to about 2 m in humid or shaded woodland
Fruit	Small globose aromatic berry, 0.7–1.3 cm across in wild material and about 1.0 cm in the INIA cultivars; skin color from green and yellow through fuchsia to red
Propagation	Cuttings; over 70% rooting within 3 months in a warm-bed trial, with IBA hormone improving rooting, or semi-ripe summer cuttings with bottom heat

Ugni molinae — the Chilean guava, murta or murtilla — is an evergreen shrub of the myrtle family Myrtaceae, native to central and southern Chile and to adjacent southwestern Argentina.^[1][2] The species was first described in 1782 as Myrtus ugni; the accepted name dates from 1848, with Eugenia ugni, Myrtus molinae and several former Ugni species treated as synonyms.^[1] Outside the native range the plant is cultivated or naturalized in Great Britain, the Juan Fernández Islands and New Zealand.^[1][2]

The berries are small, globose and aromatic, about 0.7–1.3 cm across in wild material, and skin color varies widely among ecotypes, from soft green and yellow through fuchsia to light and dark red.^[3][4] The flavor is sweet and aromatic, described as strawberry-like sweetness with guava pungency and a dried-blueberry texture, and the fruit is eaten fresh and made into jams, syrups, desserts and a traditional liquor.^[3] A Chilean governmental domestication program, INIA, has worked with the species since 1996 and released two named cultivars, 'Red Pearl-INIA' and 'South Pearl-INIA'.^[5][6]

Description

The plant is an evergreen, upright, bushy shrub.^[7][8][9] In the wild it stays low and compact on dry, exposed ground and reaches about 2 m in humid or shaded woodland; in cultivation it typically attains 1–1.5 m in 5–10 years, with a spread of 0.5–1 m.^[7][9] Plants of the two INIA cultivars measured about 1.3 m in the third year of the trial.^[5][6]

Young twigs are finely hairy with short internodes, and the small, leathery leaves are opposite and roughly deltoid, about 1.7 cm long (16 × 12 mm in the cultivar plants).^[7][3][5] The flowers are cup- or bowl-shaped, nodding, white and softly fragrant — often pink-tinged in garden clones — opening to about 0.8–0.9 cm; each flower is pentamerous and hermaphroditic with an inferior ovary.^{[9][5][10][8]}

The berry is globose. Wild fruit measured 0.71–1.31 cm in equatorial diameter and 0.25–0.40 g, with an average of roughly 16 seeds per fruit and a wide spread; the released cultivars carry about 25.5 ('Red Pearl-INIA') and 18 ('South Pearl-INIA') seeds per fruit.^[4][3][5][6] Skin color varies by ecotype and cultivar from soft green, yellow and fuchsia to light and dark red.^[3] The aroma is distinctive, with strawberry-like sweetness, guava pungency and a dried-blueberry texture carrying a floral note.^[3]

Cultivation

The species belongs to the cool-temperate, humid forests of southern Chile, where it grows as an understorey shrub from about 34–36°S in the Maule Region to about 43–45°S at the Palena River, in coastal and pre-Andean mountains, as part of deciduous Nothofagus forest and of the southern evergreen forests; it also colonizes old lava flows and open, degraded land.^[3][8][7] The climate across most of the range is cool-temperate and humid, and in the INIA germplasm study fruit polyphenol values trended higher in wetter years with more frosts — a correlation the study did not isolate experimentally.^[4] Cold is the main practical limit outside mild maritime gardens: the RHS rates the plant H4, tolerating a few degrees of frost when sheltered from cold, drying winds, with cool-greenhouse or conservatory protection recommended in colder gardens.^[9] The South Pearl-INIA application recorded no notable pests or diseases in the trial, and the RHS profile rates the plant generally pest- and disease-free.^[6][9]

Soil and water

The species prefers moist but well-drained soil; RHS garden guidance places it on chalk, clay, loam or sand across a wide pH range, while a California nursery that has grown it for years reports a clear dislike of alkaline soil.^[9][10] Native forest-edge sites are typically damp, suited to a plant of humid woodland.^[8] A Central Florida grower in zone 9b keeps potted plants under about 60% shade and reports them healthy but slow-growing, unsure how much full summer sun or wet feet the species would take there.^[11]

Sun and humidity

In the wild the species is a forest understorey shrub of partial shade and humid air.^[8][7] RHS guidance allows full sun or partial shade but recommends a sheltered position out of cold, drying winds; a California nursery finds it easy in sun to half shade, drought-tolerant once established and trimable as a hedge.^[9][10] At the warm edge of cultivation, a Berkeley, California grower (zone 10a, generally cool summers) saw potted plants shed whole sections of leaves and partially die back after heat spells up to about 32 °C (90 °F), and again during winter temperatures in the 40s °F, with only part resprouting; the grower found no consistent pattern.^[12]

Seasonal changes

The native calendar is a southern-hemisphere one: berries ripen from mid-February to mid-March in the Maule Region, from March to April in Araucanía, and from April to May in Los Lagos and Chiloé, and the INIA field harvests took place in April.^[3][4] Young plants flower quickly: in the cultivar trials, first bloom came 101–104 days after planting rooted cuttings, full bloom at 152–154 days, and the last flowers at 165–168 days.^[6][5] Winter survival reports span a wide range and cannot be reduced to one number: an in-ground plant near Battleground, Washington came through the region's coldest recorded winter, about −13 °C (8 °F), with roughly 25% dieback of weaker stems and no damage in a milder following winter; two plants planted in Vancouver, British Columbia died over a winter; and a grower overwintering potted plants in a heated greenhouse cites about −9 to −7 °C (15–20 °F) as the lowest the plant takes.^[13] Potted plants can also shed leaves under stress: the Berkeley grower's dieback followed both heat spells and cool winter weather, with partial resprouting — leaf loss in an evergreen rather than a deciduous habit.^[12] Watering through summer dry spells matters; a northern California hillside plant that had been irrigated for years died after summer watering stopped, and that grower concluded cold-air drainage was at least as important as water drainage on the slope.^[13]

Propagation

Cutting propagation is the standard route and works well. In a controlled trial at the Universidad de Talca, cuttings from two Maule provenances were rooted in a warm bed: after three months more than 70% had rooted, the Andes provenance outperforming the Coastal provenance, and application of IBA rooting hormone at 1.5 mg/g to the cutting base significantly improved rooting percentage and root quality.^[7] The RHS profile recommends semi-ripe cuttings taken in summer with bottom heat.^[9] Grower methods vary but succeed broadly: softwood cuttings dipped in gel hormone and rooted under a humidity dome in coco coir took about a month; hardwood basal cuttings cut just below the green-brown junction, stripped of lower branches, dipped in powder hormone and set in soil or perlite–peat rooted nearly every attempt for a Seattle (zone 8b) grower; a zone 7b Alabama grower rooted cuttings outdoors and found the plant took summer heat well; and a UK grower calls cuttings easy once new growth has hardened in late spring or early summer. A small side-by-side trial favored powder hormone over a liquid dip: five of six cuttings dusted with rooting powder rooted within three weeks, while none of six liquid-treated cuttings rooted and one died. Failures also occur: one grower's hardwood cuttings failed entirely, and another could not root cuttings or layers.^[14]

Seed is a slower, more variable route. One grower reported unstratified seed failing, while a nursery suggests about 30 days of cold stratification for better germination.^[14][10] Both INIA cultivars are increased from rooted cuttings, the route used through their selection.^[5][6]

Flowering, fruiting, and harvest

The flowers are hermaphroditic, and the cultivar patent records the pollination requirement as unknown.^[5] Growers nonetheless report lone plants setting fruit — one 'Kapow' plant fruited in its first year in heavy shade, and a variegated clone fruited on its own — pointing to practical self-fertility, although single-plant reports do not settle the question for all conditions or clones.^[13] The berries ripen through the late-summer and autumn window of the local season; 'Red Pearl-INIA' fruit stored well for up to 28 days after harvest in the patent trial, an unusually long postharvest life for such a soft berry.^[3][5] A two-year-old potted plant in coastal California produced a first crop of about ten berries in August.^[12]

Fruit and uses

The flavor of the berries is sweet and aromatic, with strawberry-like sweetness, guava pungency and a dried-blueberry texture, and the fruit carries a notable astringency that suits it to preserves.^[3][8] The berries are eaten fresh or dried and are made into jams, syrups, desserts and a fermented or distilled liquor; rural Chileans still consume murta dried and in jams, and historical accounts from the 1700s and 1800s describe drinks and confections made from the fruit.^[3][8] Leaf infusions were used by Mapuche and other southern Chilean peoples for urinary and intestinal complaints such as dysentery — historical ethnobotanical records, not modern medicinal advice.^[3][4][8] Fruit and leaves are rich in phenolic compounds — anthocyanins, flavonols, flavanols, tannins and phenolic acids — with strongly genotype- and season-dependent measured polyphenol and antioxidant values in the germplasm study.^[3][4] Growers in Ireland describe the fruit as very sweet with a berry-like flavor and report that the small shrubs do well outdoors there, ripening in September, with the plant regarded as a good container candidate that stays small.^[15] One grower described the tiny berries' interior as sweet and aromatic but the skin as distinctly peppery and resinous, then removed the plants; that is a single personal preference, not a consensus description.^[13]

Cultivars and selections

Cultivated murta owes its modern character to the INIA domestication program, begun in 1996 with germplasm from 103 plants collected at 36 sites across the southern Chilean range; the program built the country's first murta gene bank and, through selection and successive asexual propagation from rooted cuttings, developed two cultivars.^[3][5][6]

'Red Pearl-INIA' (US Plant Patent PP 21,273) is the more strongly colored of the pair, producing intense dark red skin with white pulp, average fruit of about 1.0 cm (0.9–1.1 cm depending on water and nutrition), about 25.5 seeds per fruit, 16 °Brix, 2.2% titratable acidity and a harvest near 1.1 kg per plant in the 2005 trial; the patent documents postharvest cold storage of up to 28 days.^[5] 'South Pearl-INIA' has light red skin, average fruit of about 1.0 cm with about 18 seeds per fruit, 16 °Brix, 2.7% titratable acidity, a higher pectin figure (1.14%) and a harvest near 0.9 kg per plant.^[6] For a home grower the differences are modest: Red Pearl is the heavier cropper with the strongest color and the documented storage life; South Pearl is less seedy with slightly higher pectin. Both are evergreen, erect shrubs of the parent species' stature and cold limits, and no notable pests or diseases were recorded for South Pearl in the trial.^[5][6][9]

A California nursery, Sacred Succulents, sells a selection it calls 'Blanco', chosen from seedlings for pink-blushed, whitish fruit that is sweeter and less tart than typical murta; the nursery notes the fruit color varies from season to season between whitish and pink. This is a nursery selection rather than a registered cultivar, and the description is the nursery's own.^[10]

Photos

References

• ↑ [1] Plants of the World Online: Ugni molinae (Royal Botanic Gardens, Kew). Accepted species first published in 1848; native range central and southern Chile to south-western Argentina, temperate biome; introductions in Great Britain, the Juan Fernández Islands and New Zealand; synonymy including Myrtus ugni (1782), Eugenia ugni, Myrtus molinae, Ugni bridgesii.

• ↑ [2] GBIF backbone species record 3185043: Ugni molinae. Accepted status with synonym list; vernacular names (Chilean guava, murta, murtilla, strawberry myrtle, murta-do-chile, goyavier du Chili, murtillo, myrtovka ovocná).

• ↑ [3] Revisión sobre composición química, componentes funcionales y actividades biológicas de las hojas y fruto de Ugni molinae (SciELO Chile, Chilean Journal of Agricultural & Animal Sciences ex Agro-Ciencia 34(1), 2018). Peer-reviewed review of murta botany, germplasm-domestication history, regional ripening windows (citing Torres et al. 1999), ecotype fruit colors (citing Scheuermann et al. 2008), fruit aroma description (citing Ah-Hen et al. 2013), traditional use and chemistry.

• ↑ [4] Alfaro et al. 2013, "Influence of genotype and harvest year on polyphenol content and antioxidant activity in murtilla (Ugni molinae) fruit", Journal of Soil Science and Plant Nutrition 13(1):163–175, doi:10.4067/S0718-95162013005000007. Original germplasm study (three INIA genotypes, Puerto Saavedra, April harvests 2006–2011); wild fruit equatorial diameter 0.71–1.31 cm (citing Seguel et al. 2000); genotype- and season-dependent polyphenol/antioxidant values; leaf-infusion traditional-use context.

• ↑ [5] US Plant Patent PP21,273 P3: Murtilla plant named 'Red Pearl-INIA' (Google Patents). Primary cultivar record: INIA gene bank origin (103 plants, 36 sites, program from 1996), rooted-cutting propagation, botanical description (evergreen erect shrub, 131 cm in the 2005 trial), fruit 0.9–1.1 cm, 25.5 seeds per fruit, 16 °Brix, 2.2% acidity, yield near 1.1 kg per plant, 28-day postharvest storage, bloom timing, pollination requirement unknown.

• ↑ [6] US Patent Application 2008/0313781 A1: Murtilla plant named 'South Pearl - INIA'. Primary cultivar record from the same INIA program (priority from Chilean Plant Variety Rights application 732, filed 2007-03-19): light red skin, fruit about 1.0 cm, 18 seeds per fruit, 16 °Brix, 2.7% acidity, pectin 1.14%, yield near 0.9 kg per plant, bloom timing, no notable pests or diseases.

• ↑ [7] Doll et al. 2012, "Propagación de estacas y concentración de taninos y flavonoides en hojas de dos procedencias de Ugni molinae de la región del Maule (Chile)", Bosque (Valdivia) 33(2):203–209, doi:10.4067/S0717-92002012000200010. Original rooting trial (warm bed, two Maule provenances, IBA 1.5 mg/g; over 70% rooting at 3 months) and native growth-form descriptions.

• ↑ [8] "Phytochemicals and Traditional Use of Two Southernmost Chilean Berry Fruits: Murta (Ugni molinae) and Calafate (Berberis buxifolia)", Foods (MDPI) 2020. Peer-reviewed review (PMC full text): evergreen habit, range and forest habitat (deciduous Nothofagus and southern evergreen forests), astringency, and historical traditional-use records (Molina 1782, Gay).

• ↑ [9] RHS Gardening plant profile: Ugni molinae (Chilean guava / strawberry myrtle). Size, evergreen habit, flowers, soil and site preferences, hardiness H4, semi-ripe cutting propagation, patio/container suitability, pest and disease rating.

• ↑ [10] Tropical Fruit Forum topic 46906: Chilean guava, or something else?. Thread including the Sacred Succulents nursery description of Ugni molinae and of its 'Blanco' selection (cup-shaped white-pink flowers, fruit taste, alkaline-soil dislike, sun to half shade, drought tolerance, hedge trimming, 30-day cold-stratification note) and a northern California grower's photos and local performance report.

• ↑ [11] Tropical Fruit Forum topic 39866: Growing Ugni molinae in Central Florida. Grower report (zone 9b, potted plants under about 60% shade): healthy but slow growth; full-sun and wet-feet tolerance untested in that climate.

• ↑ [12] Tropical Fruit Forum topic 53763: Help with chilean guava / ugni molinae dyoff issues?. Berkeley, California grower (zone 10a): potted-plant dieback and leaf drop after heat spells near 90 °F and in cool winter weather, partial resprouting, first small harvest in August.

• ↑ [13] Growing Fruit forum topic 1429: Chilean Guava. First-hand reports: Battleground, Washington in-ground survival to about 8 °F with roughly 25% dieback; Vancouver winter losses; 15–20 °F greenhouse-keeper guidance; 'Kapow' and variegated-clone single-plant fruiting; peppery-resinous skin taste report; a northern California hillside plant lost without summer irrigation.

• ↑ [14] Growing Fruit forum topic 34644: Ugni Molinae/myricoides (Chilean Guavas) Propagation?. Multiple grower propagation reports: softwood cuttings under humidity domes, hardwood basal cuttings with powder hormone, outdoor rooting in zone 7b, UK late-spring cuttings, powder-versus-liquid hormone comparison, mixed failures, unstratified seed failure.

• ↑ [15] Reddit r/GardeningIRE: Chilean Guavas ripening now. So delicious!. Ireland growers: outdoor ripening in September, sweet berry-like flavor, container suitability.

Image credits

• Ugni molinae kz01.jpg — shrub in native habitat near Alerce Costero National Park, Los Ríos Region, Chile: Kenraiz, file page, CC BY 4.0.

• Ugni molinae flowering (53136865208).jpg — flowers, Valdivia Province, Chile: Bodo12345, file page, CC BY-SA 2.0.

• Ugni molinae.jpg — foliage and fruit of a cultivated plant, UK: MPF, file page, CC BY 2.5.

• Ugni molinae fruits.jpg — fruit: RichardF42, file page, CC BY-SA 3.0.