How to Care for an Aloe Polyphylla (Spiral Aloe)
The Aloe polyphylla (spiral aloe) is native to the mountains of South Africa where it grows in rocky, mineral-rich soil, from rocky crevices, and on high, grassy mountain slopes. Despite its plump leaves, adult plants are fairly cold-hardy and can apparently survive being covered by snow, but they do not thrive in temperatures over 80 degrees. Six or more hours of cool sun is ideal, so morning or dappled sun is preferred to a hotter afternoon sun. Signs of excessive heat or dryness are brown-tipped or shriveled leaves.
Spiral aloes will look their best and be healthiest when planted in the soil versus a container. Containers can easily overheat and dry out causing brown tips. Soil-grown spiral aloes also seem to be more disease- and pest-resistant than container-grown ones, probably due to benefits of the Soil Food Web.
If you must grow yours in a container, then try to avoid synthetic fertilizers and seek out potting mixes that contain more coir coco fiber versus peat moss. Cactus potting mixes may not be ideal, so mix regular potting mix with 20 % pumice to make your own potting mix. Liquid organic fertilizers are preferred for containers, such as fish emulsion, “Tappin’ Roots All Stages,” or “Moo Poo Tea” applied about 1 to 4 times per month during the growing season (late winter, spring, and fall). They will normally go dormant or semi-dormant during our warmer summer months.
Spiral aloes seem to prefer more frequent watering than most other succulents. When the plant approaches dryness, it is time to water it again. Water deeply to 12” in depth and wait until it approaches dryness before watering again. A moisture meter comes in handy to determine the moisture content.
Good drainage is essential, so planting on mounds or hillsides is ideal. If the soil has a heavy (moldable) clay content, then mix in the following amendments with the natural soil:
About 20% to 25% pumice and/or decomposed granite (if the clay is moldable)
About 15% of a quality compost or aged manure* (for most other soils)
About 10% wood fines or wood shavings* (for most other soils)
Note that black soil is indicative of healthy, nutrient-rich soil, regardless of how hard it may seem. Amending and mulching the soil with compost or aged manure will greatly improve the porosity and health of the soil over time due to the interactions of the soil microbes, insects, and worms.
*Recommended amendments/mulches are “Grower’s Magic” (aged horse manure with shavings) from Soil Farm in Half Moon Bay or “Amendment Mix” from Lyngso Garden Materials. I use these amendments as a 1” mulch (top dressing), applied in the early fall and again in the early spring or as it decomposes. Keep it away from any thick leaves to avoid potential rotting in wet winters.
Note: Seed-germinated spiral aloes have been observed to spiral earlier than tissue-cultured ones—when they reach about 8” to 12” in diameter. Seed-germinated aloes seem to produce fewer offsets (pups) than the tissue-cultured ones.