In this edition of Beyond Broccoli (see parts one, two and three for background) we’re going to start exploring some specific species and subspecies (varieties, groups, etc.) within the genus Brassica. Rather than address each species systematically, I’ve decided on an approach based on the plant parts we usually consume. Never fear, I will inform you when introducing each plant how they fit into the genus.
So let’s start at the bottom, with root vegetables.
Turnips (Brassica rapa subspecies rapa) are possibly one of the first domesticated crops in the B. rapa species. This fascinating article discusses a study that points to human domestication beginning 4000-6000 years ago in Central Asia. Both the root and the leaves are commonly eaten, and both have a pleasantly spicy-bitter flavor. There’s a lot of variation in the size and coloration of the roots, from small and pure white to large and red, with yellowish-white and purple also available. Most are round, but some of the Asian types are elongated. I wrote a whole post about turnips last year since I love growing them so much. They are quick (30-50 days) and can be grown in both spring and fall, germinating well in cool or warm soil as long as you keep the seedbed well-watered. Definitely protect them with a row cover so you can eat the leaves as well. I like the roots raw in salads, stir-fried, roasted, or pickled.
It’s easy to confuse turnips and rutabagas, since they are both grown for their roots, but actually rutabagas belong to a different species, Brassica napus (subspecies rapifera). Rutabagas are larger and take longer to mature, making them a better crop for fall growing and a bit of a challenge with our ever-warming autumn weather. There are several commercially available varieties that look pretty similar; this is not a vegetable that’s been bred into lots of different forms as with turnips. The name comes from the Swedish rotabagga, meaning round root; they are also known as swedes, Swedish or yellow turnips, and, in Scotland, neeps. This is definitely a vegetable of northern European heritage, but can be used in many cuisines. Rutabagas get a bad rap in the kitchen but don’t deserve it; try roasting to bring out the naturally sweet flavor.
Both turnips and rutabagas were carved as jack-o-lanterns before American pumpkins took over that role.
Rutabagas also have their own sport; check YouTube for videos on the International Rutabaga Curling Championship at the Ithaca, NY farmers market.
Kohlrabi (Brassica oleracea var. gongylodes) is not a root crop, but since the part of the plant we eat most often is the swollen stem, it’s kind of like an above-ground root. This is a super-easy vegetable to grow, and one that will impress your family and friends since it is just so weird-looking.
Kohlrabi is a pale green vegetable with purple-skinned variants. They are all greenish-white once you peel them (which I would advise if you don’t pick them quite small), so choose whatever color appeals to you. There are many open-pollinated and hybrid choices. Kohlrabi grows in both spring and fall and is ready to harvest in around 60 days from seeding. There are a few giant types that are grown in fall only and harvested into early winter, taking longer to mature. I don’t have personal experience with these but they should work in our climate if you give them enough time.
Kohlrabi has a mild cabbagey flavor that’s appealing raw (great dipping veggie) or cooked. Don’t overcook it; a light fry or braise that lets it keep a bit of its crunch is sufficient. I always eat the leaves, too, since they don’t get tough during the plant’s speedy growth. Just think of them as kale. “Kohlrabi” is literally a “cabbage turnip” even though we don’t eat the root and the leaves don’t form a head; it’s still somehow reminiscent of both.
What do you know – we’ve covered three different species of brassica in this post! We’ll visit them all again (plus one more) next time when we talk about leafy greens.
By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.