Echinopsis oxygona
| Light | Bright light with some shade from the harshest afternoon sun |
|---|---|
| Water | Regular in the growing season, letting the mix dry between waterings; keep dry in winter |
| Soil | Fast-draining but not lean; a gritty mix with some organic matter (see Soil and potting mix) |
| Temperature | Hardy to light frost if kept bone dry (to about USDA zone 8b); safest kept above freezing |
| Propagation | Offsets (easiest); also seed |
| Toxicity | Non-toxic to cats and dogs |
Echinopsis oxygona is a clustering, globular to short-columnar cactus from the grasslands of southern Brazil, Uruguay and north-eastern Argentina, prized for the enormous, sweetly scented trumpet flowers it opens on summer nights. Its pale pink to soft lavender blooms — sometimes near white — can span 15–25 cm from base to mouth, towering over a plant that stays comparatively modest, and the species offsets so freely that a single plant soon becomes a crowded cushion. These traits have earned it the common name pink Easter lily cactus, and it remains one of the easiest and most rewarding Echinopsis for the beginner.
Description
Echinopsis oxygona forms a solitary body when young that soon begins to pup, eventually building up into a low mound of heads. Each stem is glossy green, globe-shaped to shortly barrel-shaped, and typically reaches 10–15 cm across, divided into a dozen or more broad, well-defined ribs. The areoles carry short, stiff spines that vary from pale to brownish; they are present but not fierce, and the plant reads as ribbed and green rather than densely armed.
The flowers are the whole point. Long buds emerge from areoles on the flanks of the stem, extend on a slender, scaly and slightly hairy tube, and open after dark into a wide trumpet of pale pink to lilac tepals with a paler throat. They are strongly fragrant and, like most night-blooming Echinopsis, last only a day or so before collapsing — but a well-grown clump will throw flush after flush across the warm months.
Distribution and habitat
The species is native to the temperate grasslands and low hills of southern Brazil (notably Rio Grande do Sul), Uruguay and the neighbouring provinces of north-eastern Argentina. It grows among grasses and low scrub in soils that are often more loamy and better watered than the harsh mineral ground favoured by many desert cacti, and it experiences a genuine cool, damp season rather than year-round drought. This grassland origin is why the species tolerates more moisture and a touch more organic matter than a strict desert cactus would.
Cultivation
Echinopsis oxygona is famously forgiving and a fine plant to learn on. Give it bright light — enough to keep the body tight and encourage flowering — with a little shade from the fiercest afternoon sun in hot climates. Because it comes from richer grassland soils, it appreciates a mix that drains fast but is not purely mineral; a gritty medium with some organic content suits it well. Water regularly through the growing season, allowing the top of the mix to dry between drinks, then reduce sharply as autumn cools.
A cool, dry winter rest is the single most important thing you can do for flowering: keep the plant nearly dry and out of freezing temperatures from late autumn until growth resumes in spring, and it will reward you with a heavy set of buds. The species is hardy to light frost when bone dry but is safest kept above freezing. Established clumps are hungry and quick, so an occasional dilute feed in summer and periodic repotting into fresh mix keep them vigorous. See Watering for general technique.
Propagation
This is about as easy as cactus propagation gets. The plant produces offsets prolifically, and these can simply be twisted or cut away, left to callus for a few days, and set on a barely moist mix to root — see Propagation — offsets and Propagation — cuttings. Seed is also straightforward and is the route to genetic variation and to the hybrid swarms the genus is famous for; sow on a warm, humid surface as described in Propagation — seed. Because offsets are so abundant, most growers never bother with seed unless they are breeding.
Cultivars and hybrids
Echinopsis oxygona has long been a parent in the wider world of Echinopsis hybridising, where its big, well-formed flowers and easy nature are valued. It crosses readily with related species and has contributed to countless garden hybrids selected for larger or more vividly coloured day-lasting blooms. It is also one of the classic old "hedgehog" or "sea urchin" cactus passalong plants, shared between growers for generations under a tangle of names. See the Echinopsis genus page for an overview of the hybrid groups.
Common problems
- Rot — the main risk, from a waterlogged mix or from watering during the cold winter rest; stems soften and discolour from the base.
- Etiolation — too little light makes the stems pale and stretch, and discourages flowering.
- Shy flowering — almost always a sign the plant was kept too warm and too wet over winter; a proper cool, dry rest fixes it.
- Pests — mealybugs (white fluff in the areoles and among the crowded offsets) and red spider mites are the usual offenders; see Pests and diseases.
See also
- Echinopsis — the genus overview
- Propagation — offsets · Propagation — seed · Soil and potting mix · Watering · Repotting