Say it: hair-ISS-ee-uh mar-TIN-ee-eye. Common names: moon cactus, harrisia cactus, Argentine jungle cactus.
Where it grows
Northern Argentina and Paraguay, scrambling through dry forest and scrub. It has escaped cultivation in Australia, Hawaii and South Africa, where it's a serious weed — which is why we can't ship it to Hawaii.
Size and growth
Long, slender, sprawling stems with a few ribs and short spines, climbing or trailing 6–10 feet. Fast and vigorous; gives it something to lean on or let it tumble from a large pot.
Flowers and fruit
Enormous white flowers up to 8 inches across open at night in summer with a sweet fragrance, then collapse by morning. Followed by round red fruit full of seed. Plants flower young, often at 3–4 years from seed.
Care
- Light: full sun to bright shade; happier than most cacti with some shade.
- Water: regular in summer, light in winter.
- Soil: fast-draining with some organic matter.
- Cold: hardy to around 25°F briefly.
From seed
Very easy, germinating in 7–14 days, with fast seedlings. One of the quickest routes to a night-blooming cactus.