A shrubby kale three to four feet tall, an onion that sets its bulblets on the tip of the flower scape: perennial vegetables are planted once and cropped for years on end. Closer to the wild species they came from, their taste is stronger — give them a sunny, well-drained spot and the harvest is always ready to reap.
Many kinds of vegetables can provide a harvest for several years.
No need to till and sow every year… and the crop is always ready to reap!
Perennial vegetables are often closer to the original wild species they were derived from. Their stronger taste tickles the taste buds of everyone who knows what real food tastes like!
These hardy species grow in most temperate climates. Give them a spot in a flower bed or set aside a sunny spot of the vegetable patch.
In this selection, you’ll find:
1 – Perennial cabbage: ‘Daubenton’
2 – Sea kale: a perennial kale
3 – Perennial onion: tree onion
4 – Wild leek, a tasty perennial variety
All four are planted once and cropped for years, but they differ in size, in the part you eat and in when that part is ready. Use the table to pick the one that suits your plot before reading the detail below.
| Vegetable | Height | What you harvest | When | Site |
|---|---|---|---|---|
| ‘Daubenton’ perennial cabbage | 3 to 4 ft (1 to 1.2 m) | Small tender heads, one per stem | Cut as needs arise; more sprout in their place | Full sun, well-drained soil, compost at planting |
| Sea kale | Around 2 ft (60 cm) | Blanched young stems, plus the fragrant flowers | Cover for blanching in late winter to early spring | Full sun, deep dry soil, sheltered from strong winds |
| Tree onion | 1½ to 3 ft | Bulblets formed on the flower scapes, and the leaves | Bulblets after flowering; leaves all winter | Full sun, rather sandy and moist soil, no manure |
| Wild leek | Clump of finger-thick stems | Blanched white stems from an ever-growing clump | Late summer through to late spring | Sun or part shade, loose soil richly manured |
Between them they cover the whole year, which is the real point of a perennial vegetable bed.
This is one of the more common types of tree cabbage. Perpetual kale (or cabbage), as it’s also known, grows into a shrubby 3 to 4-foot tall shrub (1 to 1.2m). Every stem produces a small, tender head of cabbage which tastes similar to broccoli and white cabbage. Harvest as needs arise by cutting a head off. More will sprout up in its place! These young cabbage heads are delicious grated raw in a salad, and they’re also tasty when prepared like other cabbages in stews or chop-suey.
Plant this Brassicaceae in full sun in a spot where the soil drains well. Add compost or very ripe manure upon planting. Topdress with the same every year to make sure yields stay on par. Propagation is very easy, simply plant offshoots to a nearby spot, that’s all! It rarely goes to seed. As an added benefit, it is highly resistant to both cabbage white and the turnip flea beetle.
Sea kale, probably an ancestor of today’s cultivated crops, is also a perennial. It grows among the coarse rocks and sands along the coast of the English Channel and the Atlantic Ocean. Lobed leaves and white blooming in late spring make it a great ornamental flower bed.
In England, young stems barely blanched are much appreciated for their nutty flavor. To remove the bitterness, cover the plant in late winter-early spring with an upside-down terra cotta pot or straw. This will make the young stems grow white instead of green, and they’ll be as soft as young asparagus! The fragrant flowers are also edible, they’re an excellent addition to tossed salads.
Plant the sea kale in full sun preferably, in deep soil that is dry and not too acidic. It’ll do fine in poor soil. The plant grows up to around 2 feet tall (60cm) and you should protect it from strong winds. Sow under a cold frame in early spring or mid-autumn or propagate from roots in midwinter. Take note that if you encounter the plant in the wild, it’s a protected species!
It’s called a perennial onion because you don’t need to pull the plant out to eat its bulbs. It can stay in place for years. Simply harvest the bulblets that form on the tip of flower scapes after the blooming. It has other names, too: Egyptian onion because that’s where it comes from, rocambole onion, walking onion, and also Spanish shallot as a reference to its flavor. The uncanny, top-heavy silhouette, blueish evergreen leaves and cute pink flower balls in Summer make it a fun plant to add to the garden.
The green stems grow 1½ to 3 feet tall, they advantageously replace leek or Welsh onion. You can harvest the leaves all winter long. The small onions, when mature, are delicious if you pickle them, and they’re very tasty both raw and cooked. Use them as you would other onions for a pleasant, richer flavor.
In spring and in fall, plant the bulblets or sow the seeds, in rather sandy and moist soil, with full sun, or in pots to decorate your deck or balcony. Avoid manure and the like, it tends to make bulbs rot underground. Space plants 12 inches (30 cm) apart. Tree onion catawissa is a sub-variety that has a slightly blander taste, but it’s much hardier.
These very interesting perennial leek indeed produce a clump of finger-thick stems that can be harvested anytime. The clump just keeps growing, year in, year out! They bloom very late in the season, and a key advantage of it is that they resist both allium fly and cold temperatures. Ridge twice a year to make stems grow white below soil level. Both are tasty species of leek, with a somewhat sweetish flavor that makes them ideal for soup, omelet and quiche. Great for seasoning salad, and, if you’ve got a lot, baked in the oven.
Purchase and plant small bulblets in summer, or split the leafy clumps in other seasons. 10 inches (25 cm) is a good spacing, in sun or part shade. This leek is content with loose soil, richly manured, with little watering. Harvest can begin late summer and last until the end of spring. In summer, leaves dry out because the plant goes dormant when it’s too hot.
