Illustration
Midnight Blue
Agapanthus 'Midnight Blue'
Midnight Blue blooms from June through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Midnight Blue
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 7–11. Expect it to reach about 24 in tall and 20 in wide at maturity, in roughly 2 years (checked).
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 Midnight Blue
Midnight Blue 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 Midnight Blue get?
24 intall5 ft 7 inan adult20 inwideSee Midnight Blue 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
Midnight Blue's height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil, diseases, pests and toxicity were checked against 5 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.
- RHSRoyal Horticultural Societyheight, spread, sun, water, bloom months and color, years to mature size, soil, diseases, pests and toxicity
- farreachesfarm.comFar Reaches Farmheight, hardiness zones, sun, water, bloom months and color and trait tags
- Missouri Botanical GardenPlant Findersun, water, bloom months and color, trait tags and diseases
- NC State ExtensionPlant Toolboxbloom months and color, soil, diseases, pests and toxicity
- University of Wisconsin HorticultureUniversity of Wisconsin-Madison Extension, Wisconsin Horticulturetoxicity
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Midnight Blue
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.