Why this nutritious garden vegetable is a perennial ornamental wonder

Why this nutritious garden vegetable is a perennial ornamental wonder

Isn’t it about time you grew your own asparagus? This nutritious vegetable is not getting any cheaper, and yet it is one of the easiest and most economical to grow. If you plant a plot of asparagus this fall, you may be able to harvest from it as early as next summer. However, where diameter of spears is less than pencil size, it would be advisable to hold off on harvesting until the following year. When you harvest skinny spears, you decrease plant vigor and will get fewer spears the following year. Once your asparagus plot is well established in about three years, you will harvest for up to ten weeks, starting in the spring.

During the first half of the 20th century, there were commercial asparagus farms from Van Nuys to Newhall, proof positive that our area is highly suitable for growing this crop. The advantage of growing asparagus, as opposed to other crops, is that plants are perennial and will produce for several decades or more.

Asparagus spears grow from subterranean rhizomes. Plant in soil that drains well but, as with all vegetables, preparation is the key to success. If you are planting crowns (asparagus stem bases plus roots), dig trenches eight to ten inches deep and a foot wide. Position asparagus crowns at the bottom of the trenches eighteen inches apart. It would be advisable to put some phosphate fertilizer under the crowns to accelerate root growth. Firm soil around the roots and cover crowns with soil but do not fill the trench.

As the plants develop, backfill trenches with compost-enriched soil, leaving growing tips exposed. By the end of the season, plants should be growing above ground level and trenches should be filled to the top. Where soil drainage is poor, plant in raised beds.

Ideally, crowns are planted in the fall. The first spring, unless spears are at least 1/2 inch thick, refrain from harvest and wait until growth has turned completely brown before cutting all growth to the ground.. The second spring, harvest for four to six weeks, and the third spring harvest for up to ten weeks. Beyond ten weeks, let any spears that form “fern out” so that they can provide food for rhizomes that will nourish next year’s crop. Harvest asparagus spears, which should be cut at an angle so as not to injure adjacent spears, below ground level.

Asparagus is dioecious, in the manner of date palm, pistachio and carob trees, meaning that it has separate male and female plants. Female plants are less robust since they produce seeds, sapping their strength so that, over time, an asparagus planting will consist largely of male plants. However, there are also hybrids that consist entirely of male plants. Just make sure the varieties you select are heat resistant.

  • Artichokes on Las Posas Road near Malibu. (Photo by Joshua Siskin)

  • Chinese dwarf banana Musella lasiocarpa. (Photo by Joshua Siskin)

  • Asparagus clump following harvest. (Photo by Joshua Siskin)

  • Alpine strawberry Fraise des Bois. (Photo by Joshua Siskin)

  • Lobstser claw Heliconia. (Photo by Joshua Siskin)

  • Canna Tropicana foliage in a vase. (Photo by Joshua Siskin)

  • Giant bird of paradise Strelitzia nicolai. (Photo by Joshua Siskin)



You can also purchase asparagus seedlings growing in pots at the nursery this time of year or order them online at gurneys.com. Alternatively, you can always plant asparagus seeds, which is a more economical approach. Asparagus plants that grow from seeds — although you will have to wait longer for them to develop — may actually be more robust, several years down the road, than plants grown from crowns.

Asparagus demands its fair share of water and fertilizer to produce large crops. Prior to planting – and each spring prior to the emergence of new growth – you can apply 1-1/2 pounds of 10-10-10 fertilizer per 100 square feet of growing area. Asparagus soil should be kept moist but not wet. However, better to err on the dry side since asparagus plants will rot in soggy soil.

If you refrain from harvesting asparagus spears, they will flower and produce seeds. Some people recommend growing edible asparagus even if you don’t harvest it because of its ornamental appeal. Unharvested spears grow into 4- to 6-foot extravaganzas that include ferny foliage and attractive flowers. At any time, however, you may choose to start harvesting the spears when they are seven to nine inches long, bearing in mind that an asparagus patch may continue to be productive for up to 50 years.

Asparagus is more than a vegetable rich in vitamin A. It is a genus of plants with highly ornamental foliage. Fern asparagus (Asparagus setaceous) is a vining plant with the softest, laciest leaves that you will ever see. It goes well in botanical arrangements of every description. Myers’ asparagus (Asparagus densiflorus ‘Myersii’) is sometimes called foxtail asparagus on account of its shoots that develop into irresistibly fluffy tail-like appendages. Asparagus retrofractus has large foamy sprays of foliage. Asparagus densiflorus ‘Sprengeri,’ popularly known as asparagus fern, is a sturdy ground cover spreading out in waves of foliage. It needs no water once established and will eventually produce pea-sized red fruit. However, it is highly invasive, making it a great candidate for planting on a slope where nothing else will grow, but a major headache when planted in the vicinity of other garden ornamentals. Warning: Although the above ornamental asparagus species have soft foliage, they are adorned with thorns so pruning them with gloves is recommended.

Speaking of edibles recommended for fall planting that will perpetuate themselves for years and years – globe artichokes, rhubarb, and strawberries come to mind. Artichoke plants have stunning, deeply cut silvery leaves. You can grow them from seed although they are usually propagated – and sold in nurseries – as rooted suckers taken from established plants. In other words, once you have an artichoke plant or two, you will have more of them forever if you like. In fall or winter, you detach eight-inch long shoots — with roots attached – that grow out from the base of your established artichoke plants. Artichokes appreciate full sun and will produce their edible flower buds from May until September.

Rhubarb, like asparagus, is planted from crowns and grows out as a long-lived perennial clump. However, rhubarb needs some cold winter weather to truly prosper so it is more suited to the Antelope Valley than points south, although I have seen it in one front yard in Northridge and another in Studio City. Leaves and roots are poisonous, so make sure you only eat the petioles (leaf stalks) after cooking them. Rhubarb’s harvest period coincides with that of asparagus, which is roughly eight to ten weeks during spring and early summer.

If you want a big strawberry crop next spring, now is the time to put plants in the ground. Fall planting gives strawberries time to develop a robust root system before the onset of hot weather next spring. Although strawberry plants provide a good yield for only two years, you can detach baby plants that grow on runners. Plant these babies and continue your strawberry production in perpetuity. Strawberries will need consistent moisture in the root zone during spring and summer to produce maximum yields so surrounding them with mulch is highly recommended.

For a change of pace, consider planting alpine Mignonette or wild strawberries (Fraise des Bois). Most nurseries carry seed packets of alpine strawberries, which germinate with ease. Alpine strawberries are smaller and more tart than supermarket strawberries. The advantage in growing them is that they produce fruit practically year round, are adaptable to partial sun exposure and survive freezing weather.

Tip of the Week: Several memorable members of the banana family are on display at the Los Angeles County Arboretum in Arcadia. Giant bird of paradise (Strelitzia nicolai) grows at a moderate rate, yet its curving, hyperbolic trunks do increase in length about two feet per year and eventually reach 30 feet or more in height. For flowers, it shows off husky birds with purplish-black plumage and ivory crests with single extruding blue feathers but, even out of bloom, giant bird of paradise has a majestic presence that needs no flowery superlatives to be appreciated. All you have to do is look at it.

Want to simplify your life? If you allowed a multi-trunked giant bird of paradise to develop in your front yard, you would not need any other plants to create an equatorial atmosphere. Every time you looked at your giant bird, you would be transported to a languorous tropical retreat. You would have a taste of Tahiti just beyond your front door throughout the year.

If you wanted to underplant your architectonic giant bird of paradise with complementary botanical fare, Canna ‘Tropicana’ would be the logical choice. One month ago, I cut foliage from my Canna ‘Tropicana’ and placed it in a vase with water. The leaves are still looking fresh and a bud at the base of one of them has just unfurled itself in all its fiery glory. The leaves are striped in crimson, orange, yellow, and green. Canna flowers resemble irises but bloom virtually non-stop from spring through fall. Previously, I had never seen cannas that were taller than I but, at the Arcadia arboretum, I encountered a large collection of them, with orange blooms, that were more than seven feet tall.

I also met up with a wonderful display of Heliconias. Gary Hammer, the iconic Valley nurseryman and international plant explorer, once told me that heliconias, sometimes referred to as lobster claws, will grow in the Los Angeles area, in bright shade, needing a little more light than fuchsias.  Although indigenous to the warm tropics, certain heliconia species from higher altitudes, such as Heliconia spissa, Heliconia aurantiaca and Heliconia schiedeana, are hardy enough to handle average Valley winters.

Finally, Chinese dwarf banana (Musella lasiocarpa) is one of the most cold-hardy of the banana group and has found a happy home in Arcadia. Its deep yellow flowers last throughout the summer. Chinese dwarf banana grows no more than six feet tall and, although it dies back each winter, it reliably regrows from stout rhizomes with the resumption of warm weather.

Please send questions, comments, and photos to joshua@perfectplants.com.

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