Each spring, it is so exciting to watch our asparagus patch for the hearty spears that rocket up from the soil. It is one of the earliest crops in my vegetable garden and also one of the most productive.
In peak season, new spears seem to just appear out of nowhere overnight, making it sometimes challenging to keep up with the daily harvest.
Among the vegetable crops we commonly plant, asparagus (Asparagus officinalis) is somewhat unique in that it is a perennial — a plant that lives for at least three years, resprouting each spring after winter dormancy. In contrast, most crops are annuals that die at season’s end and must be replanted each year.
As a perennial, asparagus is almost in a category of its own among the vegetable garden crops. Herbs and rhubarb are the only other perennials that come to mind from the list of more conventional vegetable garden plants. However, one aspect of asparagus that truly sets it apart is the fact that is it the only common vegetable that has naturalized in the U.S. and regularly grows along roadsides, railroads, fence rows and other similar areas.
In the wild, asparagus prefers full sun and tends to favor sites with a history of disturbance. However, it can invade natural areas and occurs in woodland edges and openings as well as prairies. Although non-native, being introduced from Europe in the 1700s, it’s not invasive and typically is outcompeted by native vegetation. However, it is quite widespread in the U.S., occurring in nearly every county in Illinois with known occurrences in nearly every state.
Asparagus is a diecious plant in the lily family, which also includes leeks, garlic and onions. Being diecious, asparagus has male and female flowers that occur on separate plants. Its tiny white flowers emerge in early summer, lasting about four weeks, and are not that showy, but can be quite abundant.
Interestingly, asparagus is an insect-pollinated plant, another unique characteristic. In Illinois, most diecious plants are wind-pollinated with tiny flowers, whereas most insect-pollinated plants are monecious with large, showy flowers. Asparagus truly breaks the mold for both.
Although I just love the early harvest asparagus offers, it has posed some management issues over the years.
In spring, I tend to pay a lot
of attention to our asparagus patch, either in anticipation of the first spears or to regularly harvest. However, as the growing season continues, I often find myself paying less and less attention, which can quickly result in a tremendous weed problem. Weed pressure is the biggest issue on this otherwise-low-maintenance garden crop.
Since asparagus is perennial, we lose some of the weed-control options that can be done in the field when annual crops are absent. I found only found a few effective options for weed control, both of which have their respective limitations.
The first option is regular shallow cultivation. It works well for most of the growing season but does require consistent follow-up. It is problematic during the early season when harvesting, because too much disturbance of the soil can impact the crop of new spears coming up each day.
During harvest, I usually fall back to the second method, which is hand-pulling weeds. That requires a similar level of follow-up as cultivation but can be considerably more labor intensive based on the layout of your asparagus patch.
My patch is out of the way and right up against our garden fence, which is challenging, since weeds accumulate along the fence and are not easy to access. In my situation, the best strategy has been aggressive and consistent hand-pulling in the early growing season and through the end of harvest.
Once harvesting wraps up, apply a thin layer of mulch to limit weed growth during the rest of the season. The patch will still need weeding, but the mulch certainly helps.
If you can manage weed control, asparagus is very easy and productive plant to add to your vegetable garden. A healthy patch can easily last for two to three decades, making it well worth establishment of unique and interesting perennial.
Ryan Pankau is a horticulture educator with UI Extension, serving Champaign, Ford, Iroquois and Vermilion counties. This column also appears on his ‘Garden Scoop’ blog at go.illinois.edu/GardenScoopBlog.