Branch out from Broccoli: How to Grow Broccoflower and Romanesco

Two similar vegetables are sometimes called broccoflower. One is a trade-marked hybrid between broccoli and cauliflower, richer in vitamin A than either of its parents and also well endowed with vitamin C. Its cauliflower-shaped yellow-green heads have a sweet cauliflower-like taste.

The other is also called Romanesco broccoli. Its lime-green heads with conical florets may weigh up to 4-5 pounds at maturity. Care for the two vegetables is similar, but Romanesco is slower to mature and can grow larger. You can harvest cauliflower-type broccoflower 70 days after transplanting, but Romanesco requires nearly 100 days. Romanesco is an Italian heirloom with a nutty flavor and is a popular vegetable in fine restaurants.

How to Grow and Care for Broccoflower

Broccoflower is a cool-season crop. Northern gardeners should transplant 4-6 week-old broccoflower seedlings outside 2 weeks before the spring free-frost date (your local Cooperative Extension can tell you when that is). Southern growers may set transplants out in August for a fall harvest or (in very warm areas) plant seeds in October for a winter harvest.

Broccoflower thrives in a very rich soil with lots of nitrogen. Add several inches of finished compost or well-rotted manure to your soil before planting. You can mix in a small amount of blood meal for an extra nitrogen boost.

Mulching your broccoflower with lawn clippings (from a lawn that’s not treated with herbicides) will help to keep the soil cool and weed-free as well as providing an extra nitrogen boost when the clippings break down. Biweekly feeding with compost tea or fish emulsion will help your broccoflower to thrive.

Planting Broccoflower

Space transplants 2-3′ apart in each direction.

Set seeds 1/2″ deep and 3″ apart in rows 2 or 3 feet apart.

Thin to 2-3′ apart.

Water regularly.

Harvest when heads are 6-8″ across.

Cauliflower-like broccoflower needs less spacing than Romanesco.  So, as a guideline, use 2 feet for broccoflower and closer to 3 feet for Romanesco since it is a larger plant.

Broccoflower and Romanesco Pests, Problems, and Diseases

Broccoflower and Romanesco suffer from the same environmental problems, pests and diseases as broccoli and cauliflower.

These are a few of them:

Very small heads may be caused by shock from cold weather (some growers recommend covering plants when night temperatures drop below 50, though I’m not sure how this fits with the recommendation to transplant outside before the frost-free date) or by insufficient nitrogen. In overly warm weather (days over 86 F and nights over 77 F) broccoflower may not form heads at all.

Hollow stems may be caused by boron deficiency. To prevent this, spray plants with kelp extract every 2 weeks, or plant broccoflower where you’ve had a cover crop of clover. Hollow stems may also be caused by excessive nitrogen and overly wide plant spacings. Experiment with different spacings to find out what’s optimal for your soil.

Purple leaves indicate a phosphorus deficiency. Spray your plants with fish emulsion and add bone meal to your soil.

If your broccoflower’s leaves curl, pucker and turn yellow, you may have an aphid or whitefly infestation. Look on the undersides of leaves for tiny soft-bodied green, brown or pink insects. Aphids can be handpicked or killed with organic insecticidal soap. Ladybugs eat aphids. Soap is the best remedy for whiteflies.

Ragged holes in leaves may be caused by cabbage loopers or cabbage worms, light green yellow-striped caterpillars. Handpick them or spray with Bacillus thuringiensis.

Pinholes in your leaves are probably the work of flea beetles. Skeletonized leaves may be caused by the Mexican bean beetle. Leaves chewed to the stem suggest the presence of vegetable weevils. Pyrethrum spray may control these pests. Pyrethrum is organic but toxic to bees–spray it in the evening when pollinators aren’t active.

If your plants have yellowish spots on their leaves that grow white downy mold in wet weather, they’ve been hit by downy mildew. If you catch it early, try spraying an organic fungicide like copper or Bacillus subtilis. If it’s well advanced, remove and destroy (do not compost) affected plants.

Weak, small-headed plants with black-spotted lower leaves have rhizoctonia. This can’t be cured. Remove and destroy (do not compost) affected plants. Don’t plant cole crops on this soil in the next 3 years.

Ways to Prepare Broccoflower

Treat it as you would cauliflower or broccoli. Eat it raw in salad or with dip, pickle it, slice it into steaks, add it to casseroles, roast it, sauté it with a bit of wine, steam it and serve it with cheese sauce… Also, you can cook the leaves of Romanesco broccoli as you would kale.

Here’s a great video on how to cut Romanesco broccoli:

Want to learn more about growing broccoflower and Romanesco?

See these helpful resources:
Broccoflower from University of Arizona
Growing Romanesco broccoli from University of Wisconsin Extension