Photo: "Imperial Star Purple artichokes 3-31-20 _DSC3065" by LAGreenGrounds · CC BY 2.0

Artichoke · Globe-artichoke

Imperial Star Artichoke

Annual · Asteraceae

Imperial Star is the artichoke variety bred to produce edible buds in its first year from seed, which is what sets it apart from older perennial strains. It is a striking large plant and rewards attentive gardeners with early green buds if started early and kept growing without major stress.

At a Glance

Days to Maturity

90–100 days

Sun

8+ hours

full sun 8+ hours, though afternoon relief helps in very hot inland climates

Spacing

36–48 "

Seed Start

8–10 weeks

before transplant

Container

Not Ideal

15+ gallon pot

Height

3–5 ft

Zone Planting Guide

Your USDA Zone:

Growing Guide

Germination

Germination Time 10–21 days

Optimal Temp 70°F

Seed Depth 0.25"

Transplanting

Min Soil Temp 50°F

Harden Off 7 days

Watering

Weekly Water 1–2 "

Needs Consistent

Method Drip

Soil

pH Range 6.5–7.5

Soil Type Deep, fertile, well-drained soil with generous compost and steady moisture.

Resilience

Heat: Moderate Cold: Moderate Drought: Moderate

Common Problems

aphids

Cause: Dense folds of new growth and buds can shelter aphid colonies.

Prevention: Rinse off early infestations and keep plants vigorous but not overly lush.

botrytis

Cause: Cool wet weather and crowded foliage can rot outer bracts and leaf bases.

Prevention: Improve airflow, remove damaged tissue, and water at the base.

Nutrition

Feeding Intensity Heavy feeder

Recommended Recipes Root drench, Silica foliar, Worm castings topdress

Harvest

Buds should be full-sized, tight, and still closed, with bracts packed rather than starting to flare.

Expected Yield 1.5–4 lbs/plant

Storage 7 days — Refrigerate buds in a perforated bag with high humidity.

Sources

seed_catalog Johnny's Selected Seeds university Oregon State University Extension

Imperial Star Artichoke Planting Dates by Zone

Planting dates for Imperial Star Artichoke vary by USDA hardiness zone. Select your zone below for frost dates, start-indoors timing, and a full monthly planting calendar.

Zone 5A Zone 5B Zone 6A Zone 6B Zone 7A Zone 7B Zone 8A Zone 8B Zone 9A Zone 9B

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