Imperial

Family: Brassicaceae Vegetable

Velvety, deep-blue green curds form a tight, regal dome on sturdy stems—lush to the eye and richly flavored in the garden.

Imperial delivers a dense, fine-textured head with a pleasing snap, plus dependable side shoots for extended harvest. Ideal for roasting, steaming, and turning into creamy sauces, this is a standout broccoli for gardeners who want bold color and consistently satisfying texture from one planting.

Light: Full SunMaturity: 68 DaysHabit: Rosette

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

Milestone	Date
Start Indoors	Mar 28th
Last Frost	Apr 25th
Transplant / Sow Outdoors	Apr 25th
Harvest Begins	Jul 2nd
Harvest Ends	Oct 16th

Crop Details

Trait	Value
Days to Maturity	68
Sun Requirements	Full Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	45
Min Soil Temp (°F)	40
Min Night Temp (°F)	32
Harden Off (days)	6

Culinary Notes

Chef's Note

Imperial’s dense, fine curd holds its shape under heat—so it roasts up browned and crisp at the edges instead of collapsing into mush. The mild brassica bite turns sweet and nutty with butter or olive oil, making it especially persuasive in roasted florets or a blended creamy sauce.

Best Uses

roasting on high heat so the florets caramelize before they go soft
steaming and finishing with browned butter for a nutty, creamy gloss
making a silky broccoli-cream sauce (blend warm with stock and cream)
quick sauté of side shoots for a crisp, bitey side dish

Flavor Profile

sweet-broccoli earthiness tight, fine-textured curds clean snap with tender interiors slight brassica bite that sweetens with heat

Kitchen Pairings

lemon garlic parmesan browned butter olive oil smoked paprika

Frequently Asked Questions

What pest or disease is most likely on Brassica oleracea var. italica (calabrese/“imperial”) and how do I manage it?

Watch for cabbage worms (imported cabbageworm/diamondback larvae) because they chew irregular holes in the curd and leave frass behind. Hand-pick small larvae early and spray an appropriate Bacillus thuringiensis (Bt) product as soon as you see feeding—repeat per label after 5–7 days if activity continues. Also check leaves regularly for downy mildew/black rot symptoms (yellowing that turns dark and spreads along veins) and remove infected plants early to prevent the spread.

How often should I water during the main growing phase for Brassica oleracea var. italica, and what soil moisture level should I keep?

During head (curd) formation, keep soil consistently evenly moist—aim for the top 1 inch to stay damp, not soggy. Water deeply about 2–3 times per week depending on heat and rainfall, and reduce frequency only if the soil is staying wet longer than a day. Uneven watering can lead to loose, stressed curds and increased susceptibility to diseases.

How can I tell when Brassica oleracea var. italica (“imperial”) is ready to harvest?

Harvest when the curd is firm and tightly budded, with the individual florets still compact—before the surface starts to separate and yellow. Typical timing is around 68 days from transplanting/seedling establishment; in practice, harvest at the first clear window of tightness rather than waiting for size alone. Cut the main head with 6–8 in (15–20 cm) of stem, and keep an eye out for smaller side shoots that can be harvested after the main cut.