Illustration
Castle Wall Blue Holly
Ilex × meserveae 'Heckenstar'
Also called castle wall holly
Castle Wall Blue Holly blooms from April through May.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Castle Wall Blue Holly
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 5–7. Expect it to reach about 7 ft tall and 4 ft wide at maturity, in roughly 10 years (a house reading).
Is Castle Wall Blue Holly toxic to dogs or cats?
- Listed as toxic to dogs and cats by Pet Poison Helpline.
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
Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. 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 Castle Wall Blue Holly
Plant Castle Wall Blue Holly 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 7, spring means March to May and fall means August or September. Once settled, it blooms from April to 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 Castle Wall Blue Holly get?
7 fttall5 ft 7 inan adult4 ftwideSee Castle Wall Blue Holly 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 Castle Wall Blue Holly
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Castle Wall Blue Holly about 4 ft apart, center to center, so each plant has room to reach its full width.
Add Castle Wall Blue Holly 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
Castle Wall Blue Holly's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 14 published sources on October 13, 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.
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, diseases and pests
- Plant Addictsqueue storeheight, spread, hardiness zones, sun, water, bloom months and color, trait tags and soil
- RHSRoyal Horticultural Societyheight, bloom months and color, trait tags, soil, diseases, pests and toxicity
- NC State ExtensionPlant Toolboxheight, spread, water, trait tags, pests and toxicity
- plantdatabase.uconn.eduUniversity of Connecticut Plant Database, Mark H. Brandsun, water and bloom months and color
- springmeadownursery.comSpring Meadow Nursery (Proven Winners ColorChoice introducer)height, spread and hardiness zones
- US plant patent (Google Patents)Google Patents HTMLspread, trait tags and diseases
- Chicago Botanic GardenPlant Finderhardiness zones and sun
- hachmann.deBaumschule Hachmann (originator)height and trait tags
- Proven WinnersColorChoicewater and trait tags
- sd8973e5dcdc13bfb.jimcontent.comBundesgehölzsichtung 2010-2015, Dr. Burkhard Spellerberg and Björn Ehs...height and spread
- woodyplants.cals.cornell.eduCornell University Woody Plants Databasesoil and pests
- edepot.wur.nlP. Goossens, Proefcentrum voor Sierteelt (PCS), Dendroflora 58 (2022),...pests
- RHSRoyal Horticultural Society (second Hecken Star profile)height
How the checking works, and what each standard covers, is on the verified plants page.
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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.