Illustration
King of Hearts
Dicentra 'King of Hearts'
King of Hearts blooms from May through September.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing King of Hearts
Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 3–9. Expect it to reach about 10 in tall and 16 in wide at maturity, in roughly 2 years (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. 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 King of Hearts
Plant King of Hearts 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 3 to 9, spring means March to May and fall means August or September. Once settled, it blooms from May to September.
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 King of Hearts get?
10 intall5 ft 7 inan adult16 inwideSee King of Hearts 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 King of Hearts
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space King of Hearts about 16 in apart, center to center, so each plant has room to reach its full width.
Add King of Hearts 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
King of Hearts' height, spread, hardiness zones, sun and trait tags were checked against 8 published sources on July 30, 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.
- NC State ExtensionDicentra eximiaheight, spread, hardiness zones, sun, years to mature size and trait tags
- Perennials.com (Heritage Perennials)Perennials.comheight, spread, hardiness zones, sun, years to mature size and trait tags
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun and trait tags
- NC State ExtensionDicentraheight, spread, hardiness zones, sun and years to mature size
- Pleasant Run Nurseryheight, spread, hardiness zones and sun
- terranovanurseries.comTERRA NOVA Nurseriesheight, spread, hardiness zones and sun
- Fine Gardeninghardiness zones, sun and trait tags
- Plant Delights Nurseryheight, hardiness zones and sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about King of Hearts
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Every part holds isoquinoline alkaloids and is mildly toxic to people, cats and dogs if eaten. The sap can irritate skin, so handle it with gloves. per NC State and Penn State
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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.