If you've been hankering to plant some edibles among your ornamentals - or vice versa - asparagus is the plant to start with. It's a warm-season veggie with fernlike foliage - bright green in summer, golden in autumn - that's stunning enough to grace any ornamental border.
- The experts disagree about when to cut down asparagus foliage: in the fall to keep pests from moving in for the winter, or in spring so that the foliage can protect the crowns through the winter. The choice is yours, but if you cut in autumn, do it after a few killing frosts have struck, and then mulch the bed. If you wait till spring, cut the foliage to ground level before new spears start popping through the soil.
- Asparagus is well worth the three-year wait it takes before you can harvest your first full crop. A well-tended bed will give you tender, delectable spears year after year for a decade or more, at a tiny fraction of the price you'd pay at the supermarket.
- Choose a site where your plants won't be disturbed - and where you and they can happily coexist for 10 to 15 years.
- Grow asparagus in partial or full sun (it performs best in full sun) in soil with a pH of 6.5 to 7.0, amended with plenty of organic matter that is rich in potassium and phosphorus.
- Buy asparagus crowns (established root systems with dormant top growth) at your nursery or through a catalog. In cool regions, plant them in early spring when the soil temperature has reached about 50 degrees F. In warm regions, plant in late winter.
- Make a 7-inch-deep, V-shaped furrow (or more, depending on how many crowns you're planting) and in each one spread a handful of wood ashes, a handful of bonemeal, and an inch layer of compost or well-rotted manure.
- Soak the crowns in compost tea for 10 minutes or so and lay them on their sides on top of the organic matter, 12 to 16 inches apart, in rows 4 feet apart.
- Fill in the furrows gradually as shoots emerge, taking care not to cover any foliage; eventually, the furrow will be level with the soil surface. Don't bother spreading out the roots; they'll find their way down.
- Weed diligently and mulch heavily with chopped leaves or straw after you've filled in the furrows.
- Side-dress plants with a balanced organic fertilizer in late summer, and top the bed in organic mulch in the fall.
- Give new plantings one to two inches of water a week; after that, water only when rainfall is scant.
- Refrain from harvesting any spears during your plants? first year in your garden. Each spear needs to "fern out" so that the roots can grow stronger and more productive. The second year you can pick a few that reach about the size of your index finger. The third year, pick finger-size spears for two to four weeks in the spring. In subsequent years, take all the finger-size spears you want for six to eight weeks, or until the spears that come up are thin and spindly.
In some regions, asparagus tends to suffer from fusarium wilt. Check with your county Extension Service; if the disease is a problem in your area, order certified disease-free crowns from a reputable nursery in another part of the country.