Best Calabrese Varieties for Scotland

Calabrese is the single large green head sold as "broccoli" in UK shops. Its main failure, boltingA plant switching early into flowering and seed production, usually triggered by stress, after which leaves, roots or bulbs turn bitter or unusable. Full page → before the head forms, is triggered by hot weather, which Scottish summers rarely bring. So the variety choice here is mostly about timing: picking varieties that between them spread the harvest across a short season.

What Scotland means for the choice

Heat-tolerant, bolt-resistant varieties are the advice for warmer regions. In a cool Scottish summer they count for less. What counts is when each variety crops, so that two or three of them cover the season between them, and hardiness for the later crops. Marathon is rated H2The RHS's H1a–H7 scale for how much cold a plant can survive outdoors, H1a being tender indoor-only and H7 hardy anywhere in the UK. Full definition →, which tolerates cool conditions but not frost; the other three are H3, hardy to about -5°C, which suits an autumn crop better. The one thing no variety changes is soil: calabrese needs a pH of at least 6.8, and much of Scotland's soil is naturally acidic. The calabrese growing guide covers liming, sowing, spacing and cutting side-shoots.

Green Magic, Kabuki and Marathon hold the RHS Award of Garden Merit (AGMThe RHS's Award of Garden Merit: a UK-wide trials award for reliable performance, not a Scotland-specific recommendation. Full definition →), a UK-wide award rather than a Scottish one. Fiesta doesn't.

Marathon

Marathon is a reliable summer-cropping variety with firm, blue-green heads over a long season, and it has some disease resistance. If you grow only one calabrese, grow this. Its H2 rating means it's best cleared before the autumn turns cold, which is where the other varieties come in.

Green Magic

Green Magic matures early, with dense heads followed by side-shoots, and it has good resistance to white rust. Grown alongside Marathon, it gives the first cut while Marathon covers the middle of the summer.

Kabuki and Fiesta

Kabuki is compact, good where space is limited, and suited to autumn cropping, with small, tight heads. That makes it the choice for a raised bed or a small plot, and for the end of the season.

Fiesta is sold on its "excellent heat tolerance", which matters less here than further south. Its use in Scotland is its August to October harvest, with large, domed heads, as an alternative to Kabuki where space isn't tight.

Which one for your situation

• One variety: Marathon.
• The longest run of harvests: Green Magic, then Marathon, then Kabuki or Fiesta.
• A small plot or raised bed: Kabuki.
• An autumn crop: Kabuki or Fiesta, both hardier than Marathon.
• White rust has been a problem: Green Magic.

None of the four resists clubroot: all list it as a problem, so liming acidic ground and rotating brassicasThe cabbage family: cabbage, kale, broccoli, cauliflower, Brussels sprouts, kohlrabi, swede, turnip and more, sharing the same pests, diseases and rotation rules. Full definition → matter whichever you grow. All four also need the usual protection from caterpillars, cabbage root fly, flea beetle, slugs and pigeons. For purple and white sprouting broccoli, a different crop that gives many small spears over months, see the best broccoli varieties.

Common questions

Sources