Illustration
Dark Lord Rhododendron
Rhododendron 'Dark Lord'
Also called dark lord evergreen rhododendron
Dark Lord Rhododendron blooms from May through May.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Dark Lord Rhododendron
Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 5–8. Expect it to reach about 6.5 ft tall and 6.5 ft wide at maturity, in roughly 4 years (a house reading).
Is Dark Lord Rhododendron toxic to dogs or cats?
- Listed as toxic to dogs and cats by NC State Extension, Pet Poison Helpline and Royal Horticultural Society.
- Listed as poisonous to people by NC State Extension and Royal Horticultural Society.
Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.
What was checked
Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. 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 Dark Lord Rhododendron
Plant Dark Lord Rhododendron in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 5 to 8, spring means March to May and fall means August or September. Once settled, it blooms in May.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Dark Lord Rhododendron get?
6.5 fttall5 ft 7 inan adult6.5 ftwideSee Dark Lord Rhododendron in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Dark Lord Rhododendron
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Dark Lord Rhododendron about 6.5 ft apart, center to center, so each plant has room to reach its full width.
Add Dark Lord Rhododendron to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Dark Lord Rhododendron's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 8 published sources on October 19, 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.
- nvknurseries.comNVK Nurseries, Ontarioheight, spread, sun, water, bloom months and color and trait tags
- Plant Addictsheight, spread, hardiness zones, sun, bloom months and color and trait tags
- pridescorner.comPrides Corner Farms, Connecticutheight, spread, hardiness zones, water, bloom months and color and trait tags
- brokenarrownursery.comBroken Arrow Nursery, Connecticutheight, spread, hardiness zones, bloom months and color and trait tags
- parkseed.comPark Seedheight, hardiness zones, sun, water and bloom months and color
- pepiniere.caPépinière.ca, Quebecheight, spread, sun, water and bloom months and color
- mandysnursery.comMandy Spring Farm Nursery, New Yorkheight, spread, water and bloom months and color
- NC State ExtensionGardener Plant Toolbox, genus pagesun and trait tags
How the checking works, and what each standard covers, is on the verified plants page.
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Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.