Yes, you can cut back asparagus in the spring, which is common if fall or winter pruning was not completed. Asparagus is a perennial plant; its tall, fern-like foliage naturally dies back and turns brown or yellow with dormancy. While many gardeners prefer to remove the dead ferns in the late fall, performing the task in the late winter or very early spring is an effective alternative. This spring pruning clears the bed and makes way for the new season’s crop of spears.
The Necessity and Timing of Removing Old Ferns
Removing the previous season’s dead growth is a preventative measure that helps maintain the long-term health and productivity of the asparagus patch. The old, dried ferns can harbor overwintering pests, such as the asparagus beetle, and serve as a breeding ground for fungal diseases like asparagus rust. Clearing this debris eliminates these pest and disease reservoirs, reducing the potential for infection and infestation of the new spears.
The timing of this spring cleanup is extremely important, as the task must be completed while the plants are still fully dormant. Asparagus crowns begin to emerge from the soil when the ground temperature reaches approximately 50°F. This typically occurs in the late winter or very early spring, well before the appearance of the first tender green shoots. Waiting too long risks damaging the delicate emerging spears, which can result in a significant loss of harvestable yield and compromise the plant’s vigor for the entire season.
The dead fern material also needs to be removed to provide a clear path for the new spears and allow for effective early-season maintenance like weeding and fertilizing. Allowing the ferns to stand until they are completely brown ensures that all the carbohydrates produced by the foliage have been fully transferred back down to the crown for storage, which fuels the following year’s harvest.
Step-by-Step Spring Pruning Technique
The mechanical process of spring pruning is straightforward but requires attention to detail to protect the dormant crowns beneath the soil. Use clean, sharp pruning tools, such as hand pruners or garden shears, to make precise cuts that minimize damage to the plant tissue. Clean tools also help prevent the accidental transfer of any lingering pathogens.
The goal is to cut the old, brittle stalks down to a height of about one to two inches above the soil line. Making the cut slightly above the crown ensures the main growth point is not damaged. Never attempt to pull or tug the old ferns, as they are strongly connected to the underground crown and pulling them can cause severe damage that weakens the plant.
Once all the dead ferns have been cut, the debris must be completely removed from the asparagus bed and disposed of properly. Do not chop the old stalks and leave them as mulch, especially if you had any signs of disease or pests during the previous year. Instead, the material should be bagged and discarded, or burned if local regulations permit, to prevent any latent disease spores or overwintering beetle eggs from reintroducing themselves to the patch.
Essential Maintenance After Cutting Back
Following the removal of the dead ferns, the asparagus bed is ready for essential maintenance to prepare it for the spring growth cycle. The first step is thorough weeding, as removing perennial and annual weeds before the spears emerge prevents competition for nutrients and makes the task much easier. It is much safer to lightly cultivate the soil and pull weeds now than to disturb the emerging spears later.
Asparagus plants benefit significantly from an application of nutrients in the early spring, coinciding with the start of new growth. A generous layer of well-rotted manure or compost provides a slow-release source of nitrogen and other micronutrients that are necessary for vigorous spear production. Applying a nitrogen-rich fertilizer, such as blood meal, at this time is also beneficial, as asparagus is a relatively heavy feeder of nitrogen.
After feeding the crowns, adding a fresh, two-to-four-inch layer of organic mulch, such as straw or wood chip mulch, over the entire bed is recommended. This layer helps to suppress the germination of new weeds throughout the upcoming season, conserves soil moisture, and helps regulate soil temperature. Mulch also provides insulation that can slightly delay spear emergence, which is helpful in areas prone to late spring frosts. Monitor the bed for the first sight of the new spears, which signals the beginning of the annual harvest.