‘Costata Romanesco’: A zucchini that will make you smile

If you like zucchini, I think you’ll love ‘Costata Romanesco.’ If you don’t like zucchini, please keep reading. It may change your life.

I became acquainted with this extraordinary summer squash many years ago, and it’s the only zucchini I plant each year. Will Bonsall, well-known Maine seed-saver, and farming/gardening guru reportedly mused that it’s “the only summer squash worth bothering with, unless you’re just thirsty.” Although its Italian name is beautiful, I will refer to it as CR to save space.

Large zucchini flower
‘Costata Romanesco’ flowers are large and can remain attached for some time.
Two zucchinis
Late-season ‘Costata Romanesco’ fruits.

CR is a stunner with alternating dark green and light green stripes with white flecking, like ‘Cocozelle’ and some other Italian varieties. “Costata” means rib in Italian. Fruits develop 8-10 prominent ribs which give cross-cut slices a unique and fun look. It has a dry, meaty texture, not unlike eggplant, that holds up when sauteed, baked, broiled, steamed, or grilled. It has a distinctive flavor described as sweet, nutty, and earthy. In addition to shredding it for cakes and breads I find it makes the best zucchini fritters (see recipe below). This year, I’m freezing loads of shredded CR.

Grate, bag, and freeze extra-large zucchini fruits.
Grate, bag, and freeze extra-large zucchini fruits.

Tips for getting the most from CR:

  • This is a large plant that can easily fill a 4 ft. x 4 ft. space. Some of the sprawling stems will flop to the ground where they will root, even through an organic mulch. These additional stems increase fruiting and allow the plant to survive a squash vine borer infestation in the main stem.
Crowded garden
‘Costata Romanesco’ plants need elbow room.
Roots from a zucchini plant stem that grew into the soil.
Roots from a zucchini plant stem that grew into the soil.
  • Try planting in mid-June to avoid cucumber beetles and squash bugs. That strategy has worked for me if you also delay planting of cucumber and melon.
  • CR produces large, sturdy male flowers if you are into stuffed blossoms. Even when the fruits get overly big, 12-16 inches long and 3-4 inches in diameter, they remain tender. Larger fruits can be shredded.
  • A variety of bees cross-pollinate the flowers, especially squash bees and bumblebees. Plant annuals and perennials to feed bees through the growing season. Interestingly, one small Cornell University study in 2013 showed that CR was somewhat parthenocarpic (produces fruits without cross-pollination). Of 19 bagged CR flowers in the research study, 58% set marketable fruit without bee pollination.

Saving seeds:

  • CR is open-pollinated. With a little bit of planning seed saved this year will produce an identical crop next year (unlike hybrid cultivars).
  • Avoid cross-pollination with non-CR pollen by not growing any other members of Cucurbita pepo, a species that includes yellow summer, acorn, scallop, and spaghetti squash and most pumpkins. Cross-pollination may still occur if these squashes and pumpkins are growing in neighboring gardens.
  • Or, you can hand-pollinate female flowers.
  • If possible, save seed from multiple fruits and multiple plants. Harvest fruits when they become very large with a hardened rind that starts to turn yellow. Allow seeds to mature inside fruits for 3-4 weeks. Cut fruits open and remove, clean, and air-dry seed at room temperature. Store seeds in a sealed container in a cool, dry location. They will remain viable for 5-6 years.
Zucchini cut in half
Seeds being saved for 2021.

Zucchini fritter recipe

2 lbs. shredded zucchini

1 medium onion finely chopped (can substitute scallions)

2 eggs

1 cup panko

2 tsp. salt

1 tsp. black pepper

1 ½ tsp. turmeric

1 ½ tsp. paprika

Shred the zucchini and either squeeze out excess water by hand or allow it to drain in a colander.

Mix all ingredients and shape into patties. Fry in vegetable oil until brown on both sides. Makes 15 fritters. Serve with plain yogurt.

By Jon Traunfeld, Extension Specialist. Read more posts by Jon.

8 thoughts on “‘Costata Romanesco’: A zucchini that will make you smile

  1. Jessica K Precht September 18, 2020 / 10:35 am

    Looks like they’re not in stock in most places. Anyone have seeds to share?

    • Maryland Grows September 18, 2020 / 2:54 pm

      The 2020 seeds have not been processed yet. Check with seed companies in December.

  2. CJ September 18, 2020 / 1:16 pm

    I love the look of a zucchini plant! They are so bold and the flowers look so delicate. I have learned a few new recipes lately so homegrown zucchini is a treasure!

  3. Geri Lawhon December 11, 2020 / 10:43 pm

    Looks like a planting project for 2021. Thanks

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