‘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.

Squash Vine Borers Collapse Plants

Gardeners are made of tough stuff. We manage a brave smile when our seedlings get nibbled, our leaves go spotty and the blessed groundhogs help themselves to our harvest.  

But there is one affliction that bring tears to our eyes: squash vine borers. I just felt the shudders from those of you who’ve had a close encounter. It’s awful.  

wilted squash plant
Squash vine borers cause the collapse of squash plants.

Picture if you will a robust squash plant, deep green, full of flowers and fruit, tall enough to shade several small children. The next morning as you sip your coffee, you spy it out your kitchen window, wilted, flattened, gone.

Yes, your neighbors heard you wail.  

What happened? Squash vine borers. These insidious insects tunnel inside squash as larvae, happily munching away as they fatten. Finally they hollow out enough of the plant that it collapses, its vascular system vanquished.

Squash vine borers most often hit summer and winter squash and pumpkins. But they can go after cucumbers, gourds and melons, too.  

So how do you prevent this tragedy? There are several good preventive measures and treatments.  

One trick is to plant early. Every insect has a prime time and simply planting earlier helps you avoid squash vine borers’ window of activity. It pays to know the enemy. 

Use established transplants instead of seeds or plant squash seeds mid-June. Again, it’s all about timing.  

You can prevent flying adults from laying eggs on your plants in May and June one of three ways. Wrap a collar of aluminum foil around the lower stems. Dust or spray with spinosad or pyrethrum. Or, cover your plants with floating row covers until they flower.  

Check your squash plants daily for signs of larval feeding. If a runner suddenly wilts, there’s probably a borer in there doing its worst.  

Also look at the base of your plants for holes and tan, sawdust-like bits. As borer larva feed, they push out frass, a fancy word for insect poop. If you find any, the game’s afoot.

squash vine damage from borer larvae
Squash vine borer larvae tunnel out the inside of squash plants.

Use a knife to make a slit upward from where you see frass. Cut halfway through the stem and remove and kill the larva, a white caterpillar with a dark head. Mound soil over the cut to promote healing. 

If you’re squeamish about squishing, inject Bt – a naturally occurring soil bacteria and organic insecticide – into the wound to kill the borer.  

If you remove an infested vine, seal it in a plastic bag and put it in the trash. This prevents the larva from dropping to the ground to pupate and return to infest your plants next year. 

I just heard Arnold say, “I’ll be back.”  

It also helps to know which squash the vine borers prefer. Butternut and cushaw squash are resistant to borers. Yellow crookneck squash is less likely to get borers than zucchini.  

Don’t give up on squash. I for one will not be without butternut squash soup. And Halloween without pumpkins is unthinkable. So prepare, prevent, and treat wisely to keep enjoying squash.

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension. This article was previously published by Herald-Mail Media. Read more by Annette.

North Georgia Candy Roaster: A Winter Squash to Remember

I enjoy the variety and versatility of winter squashes but don’t consider myself a big enthusiast for these dependable garden staples. However, one cultivar that I’ve come across over the years in seed catalogs and the heirloom gardening world has always intrigued me: ‘North Georgia Candy Roaster.’ I’ll refer to it as Candy Roaster. There was something about the name, look, and description that stayed with me. I decided that 2017 would be the year to give it a try.

candy roaster squash
Candy Roaster squash can cover ground in a hurry. Watch out lawn!

Candy Roaster is a member of Cucurbita maxima, which includes turban, hubbard, banana, and buttercup winter squash plus several pumpkin varieties (including ‘Atlantic Giant’ grown by giant pumpkin growers). Vines are long, leaves are large, and fruit stems are round and get corky at maturity. Candy Roaster fruits are 18–24 inches in length, are shaped like a fat banana, and weigh 10-12 lbs. Fruit start off light yellow and mature to an orangey-beige color with interesting blue-green streaks at the flower end.

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