FIMBY: Add asparagus to your edible ornamental garden

This is another installment in our Food in My Back Yard series, devoted to edible gardening.

When you plant asparagus, you’re making a commitment. Your first good crop will likely be two or three years away. But then, those same plants can be rewarding for many years, even decades.

The idea of growing asparagus is seductive. The spears have become a common vegetable in supermarkets and restaurants. During bare-root planting season (which is now), 1-year-old asparagus crowns are readily available in local nurseries or via mail order. (Growing from seed adds another year to the process.)

Asparagus needs sun (at least 4 to 6 hours a day), good air circulation (not against a fence or a wall) and a place where you will see it every day, especially during spear season in early spring. They also need room (at least 1 square foot per plant) and excellent drainage out of the range of any overhead sprinklers.

But most of the time, you’re not growing tidy spears, but tall ferns.

For nine or 10 months out of the year, asparagus plants look like stalks of airy foliage, 3 to 4 feet tall. That can be a shock to many novice gardeners.

Those tall ferns can be an attractive backdrop in the edible ornamental garden, surrounded by annual or perennial flowers and herbs. The ferns can be trained to stand tall on wire trellises or with tomato cages; otherwise, they tend to flop over and smother nearby plants.

Raised beds are best; they help drainage. Asparagus also grows well in a horse trough or other large planter. (That brings the spears higher to view; your back will thank you.)

The greater Sacramento area has ideal growing conditions for asparagus, particularly in Delta soils; the clay helps retain moisture. (There’s a reason the Asparagus Festival is in Stockton.) These perennials benefit from dry summer weather with drip or deep irrigation by hand. They don’t like lawn or other overhead sprinklers that wets the spears and foliage. (That can cause fungal disease.) They also need a little winter chill to set their dormancy clocks in motion.

For Sacramento, choose heat-resistant varieties such as UC 157 F1 (a popular commercial hybrid), Early California, Atlas and Apollo. (Their ferny foliage stays green all summer.) These varieties are drought-resistant, too.

Because asparagus will be in one spot for a long time, work some aged manure or compost into the planting area’s native soil. During growing season (after the ferns appear), asparagus likes a little extra nitrogen to promote that foliage.

UC master gardeners recommend planting asparagus transplants outdoors in the Sacramento Valley in March, but crowns are available now. Start them indoors in January in pots and then transplant – soil, sprouts and all – as the weather warms.

In the garden, space plants at least one foot apart. To transplant crowns, make a hole 4 to 6 inches deep and wide, or create 6-inch deep furrows, 12 inches apart. Place the crown, root side down, fanning the finger-like roots out to the sides. Cover with 2 to 3 inches of amended soil (mixed with compost) and water. After the crowns sprout, fill in the hole or furrow with more amended soil.

Water-wise, they need just enough to keep their soil consistently moist but not soggy-wet, 6 inches below the surface. Winter rain is usually enough to fill their needs. In spring and the hottest parts of summer, water weekly or twice monthly; let the soil be your guide.

Most of all, asparagus takes patience, a combination of benign neglect with vigilance. You plant and you wait.

And then you wait some more. But during asparagus season starting in early February, you need to look at the bed at least once a day, sometimes two. Spears will pop up overnight (or midday) and grow quickly, sometimes 4 inches day. Miss a day and that spear can go from yummy to fern fodder.

The first year, don’t harvest any spears; let all those shoots fan out and become ferns. The foliage is pumping energy into the roots for next year’s spears.

The second year, harvest the first spears to appear and the next few over a period of two or three weeks. But let all the later shoots become ferns. The roots are still maturing.

How to harvest? With a sharp paring knife or an asparagus cutter (a special tool with a sharp forked end), cut the spear after it grows 6 to 8 inches tall about a half inch below the soil line. (Aim just below the spear’s base.)

As the years go by, the harvest period becomes longer as spears become more numerous. Spears can be cut daily or every other day for eight to 10 weeks. But always leave a few late shoots to become ferns and feed the roots.

Those ferns remain green until frost. Trim to the ground after they brown, then compost them. (Don’t leave them lying around; they’ll become winter homes for pests.)

While the ferns grow, keep the beds weeded as much as possible. Bermudagrass and bindweed can strangle asparagus plants. Pull those invaders early. (That’s another kind of vigilance.)