Blackberry jam fruit (Randia formosa) is a small shrub with fragrant white flowers and small fruit whose dark pulp tastes remarkably like blackberry jam. (Randia formosa)
Shop this plant: Blackberry Jam Fruit Tree (Randia formosa) – 3 Gal
Quick Care Summary
- Sun: Full sun to partial shade.
- Soil: Well-drained soil is essential.
- Watering: Water new plants 2-3 times a week for the first month, then weekly through the first year.
Sun
Full sun to partial shade.
Soil
Well-drained soil is essential. South Florida's sandy and limestone soils work well if water never stands; plant on a slight mound in low areas and mix in compost at planting.
Watering
Water new plants 2-3 times a week for the first month, then weekly through the first year. Established trees need deep watering during dry spells, especially while flowering and setting fruit.
Fertilizer Schedule for South Florida
Young trees: a balanced fertilizer with minor elements (such as 6-6-6 or 8-3-9) every 6-8 weeks from March through September, starting small and increasing as the tree grows. Mature trees: 2-3 applications a year (spring, early summer, late summer). Skip fertilizer from November through February. On alkaline South Florida soil, add chelated iron and manganese if new leaves are pale with green veins.
Pruning
Prune lightly after harvest to shape the tree, remove dead and crossing branches, and keep it at a pickable height.
Cold Protection
Tolerates brief dips near 30°F; protect young plants from frost.
Container vs. In-Ground
Excellent in a 7-15 gallon container; naturally compact.
Spacing
Plant 6-8 ft apart.
Flowering and Fruiting Timeline
Fruits within 2-3 years; can flower and fruit several times a year.
Harvest
Pick when the fruit turn yellow-orange and feel slightly soft. Break open and eat the dark pulp.
Common Pests and Diseases
Start with organic, low-impact fixes: good airflow, clean-up of fallen fruit and leaves, and soaps or oils before anything stronger. Always follow label directions.
Scale and mealybugs
How to identify: Small bumps or white cottony clusters on stems and leaf undersides, often with sticky honeydew and black sooty mold.
Organic-first treatment: Prune heavily infested twigs, spray horticultural oil or insecticidal soap, and control the ants that farm them.
Anthracnose and leaf spot
How to identify: Dark sunken spots on leaves and fruit, worse in rainy weather.
Organic-first treatment: Prune for airflow, clean up fallen leaves and fruit, and use copper fungicide during wet periods if needed.
Fruit flies
How to identify: Small punctures in ripening fruit that turn soft and rot from inside.
Organic-first treatment: Harvest on time, pick up dropped fruit daily, and bag developing fruit with mesh or paper bags.
Root rot
How to identify: Wilting despite moist soil, yellowing leaves, dark mushy roots.
Organic-first treatment: Prevention is the cure: plant high in fast-draining soil, never let water stand, and cut back watering in cool months.
FAQ
What does it taste like? Sweet, like blackberry jam.
How big does it get? Usually 6-10 ft, easy to keep smaller.
Related Reading
- Best Fruit Trees for Small Miami Yards and Condos
- Why Too Much Fertilizer Can Hurt Your Fruit Tree More Than None
- Cold-Hardy Fruit Trees for Florida Freezes (and How to Protect Tender Ones)
Ready to grow your own? Get the Blackberry Jam Fruit here.
