Illustration
Storm Cloud
Agapanthus 'Storm Cloud'
Storm Cloud blooms from June through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Storm Cloud
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 7–11. Expect it to reach about 3.5 ft tall and 2 ft wide at maturity, in roughly 2 years (a house reading).
What was checked
Fifteen fields were checked against named botanical sources, each recorded beside the sources that carried it, with every unsettled point written down and decided: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, soil, diseases, pests, toxicity, the plant's own names, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Storm Cloud
Storm Cloud is a summer bulb planted in spring: get it in after the last frost, once the soil has warmed, March or April in zone 8, the middle of its hardy zones 7 to 11. It is hardy in zones 7 to 11, where it can stay in the ground over winter; colder than zone 7, lift and store it before the ground freezes. Expect flowers from June to August.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 8, the middle of this plant's hardy range, start with zone 8 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Storm Cloud get?
3.5 fttall5 ft 7 inan adult2 ftwideSee Storm Cloud in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
Where these facts come from
Storm Cloud's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 8 published sources on August 20, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- smgrowers.comSan Marcos Growersheight, spread, sun, water, bloom months and color, trait tags and toxicity
- Missouri Botanical GardenPlant Findersun, water, bloom months and color, trait tags and diseases
- Plant Delights Nurseryheight, hardiness zones, sun, bloom months and color and trait tags
- diggingdog.comDigging Dog Nurseryheight, spread, hardiness zones and bloom months and color
- emerisa.comEmerisa Gardensheight, hardiness zones, water, soil and pests
- University of Wisconsin HorticultureUniversity of Wisconsin-Madison Extension, Wisconsin Horticultureheight, sun, bloom months and color and toxicity
- NC State ExtensionPlant Toolboxsoil, diseases, pests and toxicity
- University of Florida IFASUF/IFAS Gardening Solutionssoil, diseases and pests
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Storm Cloud
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
The sap irritates skin, eyes and mouth (bitter steroidal saponins), and chewing causes vomiting and drooling in pets. It is not a true lily and causes no kidney failure. per Pet Poison Helpline and North Carolina
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.